Authenticating Hadith and the History of Hadith Criticism

The following is (mostly) an extract from my book Hadith: Muhammad’s Legacy in the Medieval and Modern World (Oneworld, 2017). I have taken this opportunity to add some material as well, especially in light of debates over hadith reliability that I have seen take place since this book was published. 

Arabic and English textbooks introducing Islamic methods of hadith criticism begin with presenting the complex technical vocabulary (muṣṭalaḥāt) of hadith critics as it was formalized after the thirteenth century. These books assume that by learning this set of terms students will understand how hadith criticism operated in the early Islamic period when scholars like al-Bukhārī and Muslim were compiling their Ṣaḥīḥs. In reality, however, the critical methods of early Muslim hadith scholars were diametrically opposed to this later, rigid description. Theirs was an intuitive and commonsense way of trying to determine whether a report could be reliably attributed to a source or not—a method not unlike those employed by modern investigative reporters. To set the stage for our study of how Muslims tried to sift reliable from unreliable ‘reports’ from the Prophet ﷺ, let us imagine a journalist working today.

If our reporter tells her editor that she has a major story about a senior political figure, the editor will ask her two questions: who is your source, and is your source corroborated? How could our reporter reply? She knows that certain sources are reliable for certain information. If the president’s spokesperson announces that the president will make a visit to the UK, there is no need to double-check this information. Imagine, however, that the reporter has found a source who gives her rare and valuable information about an important issue but whom she as yet has no reason to trust. Our reporter is not going to stake her journalistic reputation on this one tip, but how does she determine the accuracy of her source’s information?

Imagine that this source tells her that there has just been an earthquake in China. Our reporter would call her contacts in China to confirm. If these contacts tell her that indeed a quake had occurred, the source has been proven correct. If no one she spoke to had noticed anything, the source’s story would be uncorroborated and our reporter would conclude that the source was unreliable. Suppose that next the source tells our reporter valuable information about the condition of the country’s economy. Again, our reporter proceeds cautiously, so she conducts thorough research and finds that the source’s information was correct. The source provides tips on a few more stories, and after checking out the information, our reporter finds that these stories are true as well. Eventually our reporter concludes that this source is reliable, and if the source provides a tip on a hot story in the future, the reporter will feel comfortable writing her story based on the source’s testimony alone.

Reporters understand that the reliability of a source is based upon the accuracy of the information they provide. The best way to confirm the accuracy of a source is to check with other sources who have access to the same information and see if they agree. Corroboration “is what turns a tip into a story.”

These two pillars of modern journalism, the reliability of a source and determining the reliability of a source or story through corroboration, are familiar to us all in our daily lives. We all know people who pass on information reliably and others who tend to forget, lie, or exaggerate. We all instinctively seek out corroboration and know when it matters and when it does not. If a student is absent for a day of class in university and hears from a classmate that the professor has changed the date of the final exam, they will not be content to take the word of just one classmate; the student will ask other students who were also in that class. If no other students heard the professor make that announcement, they will have serious doubts about the information.

Another fact is equally evident to us in our daily lives: the contents of reports we hear have a strong influence on our view of their reliability and our confidence in their transmitters. If our reporter met a source who swore that he had seen a herd of flying elephants downtown, she would probably both disbelieve him and consider him unreliable from that point on. There are generally accepted standards of what is possible and impossible. Furthermore, we all have a sense of what is important information and what is not, and we treat this information accordingly. If our reporter hears a rumor that the president is about to announce a major change in the government’s economic policy, she will want to verify this information before writing her story. If she hears that the president has changed his favorite dessert from ice cream to angel-food cake, she will probably be content to cite this information as is.

We must remember, however, that such notions of what is possible or impossible, important or unimportant, are culturally determined, and as such they may differ with time and place. If, in 1990, a student had come to class holding a small device they claimed contained any piece of music, information, or published material one could think of, the professor would have called them delusional. Today professors compete daily for attention with such devices. If a professor in the US claimed to have eaten a great dog meat dinner at a specialized dog meat restaurant, students would think this was a disgusting joke. But if the professor had just flown in from China, where dog meat has long been “a minor but regular part of the diet” and where an annual dog meat festival is held, he might be telling the truth.

While modern reporters are charged with determining the veracity of stories about what is happening in the world today on the basis of contemporary sources, the architects of the Islamic hadith tradition were faced with a more daunting task: they had to establish a system of distinguishing between true and false stories about a man who had lived over a century earlier and whose revered status cast a commanding shadow over the entire Islamic tradition.

In this paper we discuss the origins, mechanics, and development of Sunni hadith criticism. We divide its history into two periods: early hadith criticism, roughly 720–1000 CE, and later hadith criticism, from roughly 1000 CE to today. This is a study of Muslim scholarship, so notions of ‘authenticity' and ‘forgery’ mentioned here refer to the judgment of Muslim scholars of hadith and not necessarily to the methods of modern Western historians (see this paper for more on the Western historical-critical method).

The Prophet Muhammad ﷺ is the single most dominant figure in the Islamic religious and legal tradition. From the time of his emigration to Medina to debates over Islam today, to disobey directly his established teachings has been to place oneself outside the Muslim community. Because the Prophet possessed such eminent authority, early Muslims looked to his legacy to support or legitimize their different schools of thought, beliefs, or political agendas. It seems that even during the Prophet’s own lifetime he understood that people could misrepresent him. In one report, a man claiming to be the Prophet’s representative established himself as the mayor of a small town in Arabia until the Prophet uncovered his hoax and punished him.

One of the first crises to afflict the Muslim community after the Prophet’s death—the question of who would succeed him as religious and political leader—revolved around competing claims about the Prophet’s words. The supporters of ʿAlī ibn Abī Ṭālib argued that the Prophet ﷺ had announced him as his successor, while those who affirmed the successive caliphates of Abū Bakr, ʿUmar, and ʿUthmān did not. In this and many other Islamic sectarian and political disagreements, all sides agreed on what the Prophet had said but disagreed on its implications. Both Sunnis and Shiites, for example, agreed that the Prophet had said that ʿAlī was to him what Aaron was to Moses, but they disagreed on whether that meant that ʿAlī should succeed the Prophet politically.

Actually forging reports about the Prophet ﷺ also quickly became a problem. When civil war broke out openly between ʿAlī, then the fourth caliph to succeed the Prophet, and the then governor of Syria and future founder of the Umayyad dynasty, Muʿāwiyah ibn Abī Sufyān, both sides waged a propaganda war using the Prophet’s words as ammunition. ʿAlī’s supporters falsely claimed that Muhammad ﷺ had said, “If you see Muʿāwiyah ascend my pulpit, then kill him,” while Muʿāwiyah’s side countered by forging hadiths such as “It is as if Muʿāwiyah were sent as a prophet because of his forbearance and his having been entrusted with God’s word” (Muʿāwiyah had served as one of the Prophet’s scribes). There are even reports from the early historian al-Madā’inī (d. 228/843) that Muʿāwiyah encouraged the systematic forging and circulation of hadiths affirming the virtues of the other caliphs and Companions at ʿAlī’s expense (then again, these reports about Mu‘āwiya might have been made up by his opponents).

In light of how quickly the Prophet’s legacy became a tool to be manipulated by vying parties among Muslims, we should not be surprised at the veritable slogan of Muslim hadith criticism. It is the most widely transmitted hadith in all of Islam, with Muslim scholars counting between sixty and a hundred Companions transmitting it from the Prophet ﷺ: “Whoever mispresents me intentionally, let him prepare for himself a seat in Hellfire.”

During the lifetime of leading Companions like ʿUmar ibn al-Khaṭṭāb, ʿAbd Allāh ibn Masʿūd, or Anas ibn Mālik, many of whom had been with the Prophet ﷺ since his early days in Mecca, it was difficult to attribute something untrue to the Prophet without a senior Companion noticing. In fact, there are many reports documenting the Companions’ vigilance against misrepresentations of the Prophet’s legacy. ʿAlī is quoted as requiring an oath from any Companion who told him a hadith from the Prophet that he himself had not heard. When the Companion Abū Mūsá al-Ashʿarī told ʿUmar that the Prophet had said that if you knocked on someone’s door three times and they did not answer you should depart, ʿUmar demanded that he find another Companion to corroborate the report.

On a number of occasions after the Prophet’s death, his wife ʿĀʾishah objected to hadiths that other Companions related. She rejected Ibn ʿUmar’s statement that the Prophet ﷺ warned mourners that a dead relative would be punished for his family’s excessive mourning over him because she believed that it violated the Qur’anic principle that “No bearer of burdens bears the burdens of another” (Qur’an 53:38). Sometimes she corrected Companions who had misunderstood what the Prophet had said. Abū Hurayrah quoted the Prophet as saying that women, beasts, and houses could be bad omens. When Aisha heard this she “split in half in anger,” exclaiming that the Prophet had mentioned this, but only to explain that it was a pre-Islamic superstition condemned by the Qur’an. Abū Hurayrah’s extensive efforts at hadith collection in particular drew the ire and concern of some leading Companions. There is one report that ʿUmar bin al-Khaṭṭāb told him, “Indeed, I say let the Prophet’s words alone or indeed I’ll send you back to the lands of [your tribe] Daws!” 

We should remember that anxiety over excessive or careless interest in collecting hadith in no way meant that the Companions did not consider the Sunnah of the Prophet authoritative (the Sunnah being the Prophet’s authoritative precedent as a whole, with individual hadiths being pieces of information telling us about that Sunnah). And they had no problem writing hadith down when necessary; as caliph, Abū Bakr sent Anas, then a regional governor, a document with the Prophet’s commands regarding Zakat collection. ʿUmar might ask for corroboration and Aisha might object that someone had misunderstood a hadith, but this was not skepticism about hadith in general. When ʿUmar warned other Companions to “Be frugal in narrating from the Prophet of God,” early Muslim scholars understood this meant not obsessing about collecting stories about his battles and campaigns. It was not an objection to collecting hadith on law, ethics, and belief.

Hadith forgery emerged as a blatant problem when the generation of Muslims who had known the Prophet ﷺ well died off. With the death of the last major Companion, Anas ibn Mālik, in Basra in 93/711 (the last Companion to die was Abū al-Ṭufayl ʿĀmir ibn Wāthilah, who died between 100/718 and 110/728), lies about the Prophet  quickly multiplied. It is especially in the generation of the Successors that we begin seeing notebooks (ṣaḥīfahs) of hadiths, many supposedly narrated from Anas, filled with forged hadiths of a highly partisan or controversial nature.

From that point onward, the forgery of hadiths would be a consistent problem in Islamic civilization. The heyday of hadith forgery was the first four hundred years of Islamic history, when major hadith collections were still being compiled. As compilation ended, by the late 1100s any alleged hadith that entered circulation that had not already been recorded in some existing book was automatically deemed a forgery. In the great urban centers of Mamluk Cairo or Ottoman Istanbul in the fourteenth and fifteenth centuries, the masses might mistakenly think that a popular saying such as “The Muslim community is sinful but its Lord is most forgiving (ummah mudhnibah wa-rabb ghafūr)” was said by the Prophet ﷺ, but in general hadith forgery had run its course.

Political and sectarian conflicts were a major engine for hadith forgery. All the major political conflicts in classical Islamic history were accompanied by hadiths forged for propagandistic purposes. The Prophet’s access to knowledge of the future provided endless possibilities in this realm. In one hadith, the Prophet ﷺ supposedly tells his uncle ʿAbbās, progenitor of the Abbasid dynasty, to look at the stars. The Prophet foretells, “From your descendents a number like the number of the Pleiades will rule the Muslim community.” In one forged pro-Shiite hadith, the Prophet predicts that “al-Ḥusayn will be killed sixty years after my emigration to Medina,” referring to the Umayyad caliph’s massacre of the Prophet’s grandson at Karbala in 61/680. In the twelfth century, an opponent of the Seljuq Turkish sultan Sanjar forged a hadith in which the Prophet predicted that, “Sanjar will be the last of the non-Arab kings; he will live eighty years and then die of hunger.” In fact, in the early 1990s one Arab scholar claimed that he had found an old manuscript with a hadith predicting that “A leader whose name is derived from the word ‘tree’ [Bush, perhaps?] will invade and liberate a small hill fort (in Arabic, ‘Kuwait’).”

Many hadiths were also forged in legal and theological debates. Here the Sunni/Shiite schism once again has certainly produced the largest numbers of propagandistic hadiths. Less well-known conflicts have also yielded countless forgeries. In the first half of the ninth century, when the Abbasid caliphate was trying to impose its rationalist beliefs on Sunni scholars like Ibn Ḥanbal by torturing or imprisoning anyone who would not uphold the belief that the Qur’an was God’s created word and not an eternal part of His essence, pro-Sunni hadiths conveniently appeared in which the Prophet ﷺ said, “Whoever dies believing the Qur’an is created will meet God on Judgment Day with his head up his rear-end.” In eighth-century debates over whether Muslims could wear pants as opposed to robes, a hadith appeared in which the Prophet said, “O people, take pants as clothing, for indeed they are the most modest of clothes, especially for your women when they leave the house.” As legal schools solidified and competed with one another, forged hadiths appeared with statements such as “There will be in my community a man named Abū Ḥanīfah, and he will be its lamp... and there will be in my community a man named Muhammad ibn Idrīs [al-Shāfiʿī] whose strife is more harmful than that of Satan.”

Hadiths were forged to give voice to all sorts of chauvinisms. Some were virulently racist, such as a forged hadith saying “The black African, when he eats his fill he fornicates, and when he gets hungry he steals (al-zanjī idha shabiʿa zanā wa-idhā jāʿa saraqa).” Others voiced civic pride, such as the hadith “[The city of] Askalon [near modern-day Gaza] is one of the two Brides, from there God will resurrect people on the Day of Judgment (ʿAsqalān iḥdá al-ʿarūsayn ...)” or a whole Forty Hadith collection that one Aḥmad ibn Muhammad al-Marwazī (d. 323/934–5) forged about the virtues of the Iranian city of Qazvin.

Another major source of forged hadiths was the popular story-tellers (qāṣṣ, pl. quṣṣāṣ) who entertained crowds on the streets of metropolises like Baghdad. These storytellers would attribute Jewish, Christian, or ancient Persian lore to the Prophet ﷺ. In one fantastic story, someone named Isḥāq ibn Bishr al-Kāhilī from Kufa told of the Prophet meeting an old man in the desert. The man claimed to be named Hāma, the great-grandson of Satan, and to have been alive since the days of Cain and Abel. In an account resembling a Rolling Stones song, he proceeds to tell Muhammad how he had met all the great prophets, from Noah to Jacob and Joseph. Moses had taught him the Torah, and Jesus had told him to convey his greetings to Muhammad, the messenger to come.

A surprisingly large number of hadiths were forged and circulated by pious but misguided Muslims in an effort to motivate those around them both religiously and morally. One Abū ʿIṣmah was asked by his contemporaries to explain how the hadiths he narrated from ʿIkrimah, the disciple of the Companion Ibn ʿAbbās, about the virtues of reading different chapters of the Qur’an, were not narrated by any of ʿIkrimah’s other students. He replied that he had seen the people becoming obsessed with the legal scholarship of Abū Ḥanīfah and the Sīrah of Ibn Isḥāq. He had forged these hadiths to try and steer people once again towards the Qur’an.

Many of those who forged hadiths for these pious purposes were themselves revered saintly figures. The famous hadith critic Yaḥyá ibn Saʿīd al-Qaṭṭān (d. 198/813) once said, “I have not witnessed lying [about the Prophet] in anyone more than I have seen it in those known for asceticism and piety.” A venerated saint of Baghdad, Ghulām Khalīl, was so beloved that on the day he died in 275/888-9 the markets of the city shut down. Yet when he was questioned about some dubious hadiths he narrated concerning righteous behavior, Ghulām Khalīl replied, “We forged these so that we could soften and improve the hearts of the populace.”

Certainly pious figures such as Ghulām Khalīl or the scholars of religious law understood the enormity of the sin of lying about their Prophet ﷺ. How could they have contradicted their own mission of preserving his authentic teachings by doing so? Pious figures sometimes replied that the Prophet had forbidden the Muslims to lie about him, whereas they were lying for him. In the case of those early jurists who forged legal hadiths to support their school of law, it seems that they saw no contradiction between their actions and their commitment to preserving the Prophet’s teachings. After all, as one famous hadith put it, “The scholars are the inheritors of the prophets (al-ʿulamāʾ warathat al-anbiyāʾ).” It was the scholars who interpreted the message of Islam as it faced new challenges and circumstances. Phrasing their conclusions about proper acts or beliefs in the formula of ‘the Prophet said...’ was simply neatly packaging their authority as Muhammad’s representatives. As one early jurist explained, “When we arrived at an opinion through reasoning we made it into a hadith.” Hadith critics, of course, found such excuses reprehensible.

Not all forgery of hadiths was a malicious act. Early transmitters sometimes confused the opinions or statements of Companions with Prophetic hadiths, such as  Ibn Masʿūd’s saying, “Whatever the Muslims see as good is good according to God,” which was sometimes wrongly attributed to the Prophet ﷺ. Sometimes the comments of one of the hadith’s transmitters could be accidentally written as part of the hadith, a phenomenon that Muslim critics called idrāj (interpolation). Ibn ʿUyaynah (d. 196/811) narrated a hadith that the Prophet would seek refuge with God from four things: unbearable hardship, encountering misfortune, an evil fate, and the triumph of enemies. But he noted that the original hadith had only listed three things, “but I added one, and I do not know which one it is.”

Often the words of scholars or saintly figures or simply popular sayings could be accidentally elevated to the status of Prophetic hadiths. The saying “The love of the earthly life is the start of every sin (ḥubb al-dunyā raʾs kull khaṭīʾah)” was generally attributed to Jesus until it became confused with a Prophetic hadith. A legal principle used by Muslim jurists, “Necessities render the forbidden permissible (al-ḍarūrīyāt tubīḥu al-maḥẓūrāt)” was also accidentally attributed to Muhammad ﷺ. In the ninth century a hadith appeared saying “Beware of flowers growing in manure, namely a beautiful woman from a bad family (iyyākum wa khaḍrāʾ al-diman ...).” In this period another supposed hadith surfaced that “Whoever says something then sneezes, what he says is true (man ḥaddatha hadīthan fa-ʿaṭasa ʿindahu fa-huwa ḥaqq).” Neither report had any basis in Prophetic hadiths.

Hadith forgery was not limited to inventing Prophetic sayings or attributing existing maxims to Muhammad ﷺ. In light of the importance of the isnād to accessing authority in the Islamic tradition, isnād forgery was arguably more common than matn forgery. Equipping existing hadiths with one’s own isnāds or constructing entirely new chains of transmission was known as ‘stealing hadiths (sariqat al-ḥadīth)’ or ‘rigging isnāds (tarkīb al-asānīd).’

Today no one would look askance at someone who cited a hadith without mentioning its isnād. In the early Islamic period, however, ahl al-ḥadīth scholars or those who debated them could not cite a hadith without providing their own isnād for the report. A scholar who had heard about a hadith without a firm isnād or from a transmitter considered unreliable by the ahl al-ḥadīth critics could thus not credibly present his hadith in any discussion. Forging a new isnād offered a solution. ʿAmr ibn ʿUbayd (d. 144/761), who belonged to the Muslim rationalist camp known as the Muʿtazilites, whom the ahl al-ḥadīth considered their mortal enemies, was thus attacked for lying in his narration of the hadith “He who carries weapons against us [Muslims] is not one of us (man ḥamala ʿalaynā al-silāḥ fa-laysa minnā)” from his teacher al-Ḥasan al-Baṣrī, from the Prophet ﷺ. This hadith was well known as authentic among the ahl al-ḥadīth. The problem was that al-Ḥasan had not actually transmitted this from the Prophet. ʿAmr ibn ʿUbayd had heard of the report somewhere else and then tried to use it to support the Muʿtazilite position that committing grave sins assured Muslims a place in hell. But he did not have his own isnād for it. So he manufactured one from his teacher al-Hasan so that he could use it in debates.

The second major motivation to forge an isnād for an existing hadith was to bolster its reliability by increasing evidence of its transmission. According to the great hadith critic of Baghdad, al-Dāraquṭnī (d. 385/995), a whole notebook of hadiths praising human reason (ʿaql) was forged by Maysarah ibn ʿAbd Rabbihi. This book was then taken by Dāwūd al-Muḥabbir, who equipped the reports with his own new isnāds. One ʿAbd al-ʿAzīz ibn Abī Rajāʾ then stole these hadiths and provided them a new set of isnāds. Sulaymān bin ʿĪsá al-Sinjarī then did the same. A person who came across the hadiths in this book therefore could find four different sets of isnāds leading to four different scholars for hadiths that were in fact total forgeries.

Especially in the tenth century and afterwards, when rare and elevated isnāds assumed a particular value among hadith collectors, disingenuous scholars could forge isnāds with these characteristics. The famous—if totally uncritical—hadith collector al-Ṭabarānī (d. 360/971) narrated a hadith via the impossibly short isnād of three people to the Prophet: Jaʿfar ibn Hamīd al-Anṣārī, from ʿUmar ibn Abān, from Anas ibn Mālik, from the Prophet ﷺ. The fact that al-Ṭabarānī was the only hadith scholar to narrate from the transmitter Jaʿfar ibn Hamīd strongly suggests that this Jaʿfar might have been a purveyor of forged elevated isnāds, which a collector like al-Ṭabarānī would have found irresistible.

As false attributions to the Prophet ﷺ multiplied in the late seventh century, how were those Muslims who sought to preserve his authentic legacy to distinguish between true and forged hadiths? While the ahl al-raʾy scholars in Iraqi cities like Kufa attempted to rise above the flood of forged hadiths by depending on the Qur’an, well-established hadiths, and their own legal reasoning, the school that would give birth to the Sunni tradition, the ahl al-ḥadīth, evolved the three-tiered approach to determining the authenticity of a hadith. The first tier was demanding a source (isnād) for the report, the second was evaluating the reliability of that source, and the third was seeking corroboration for the hadith.

The processes of this three-tiered critical method did not emerge fully until the mid eighth century with critics like Mālik (d. 179/795) and Shuʿbah ibn al-Ḥajjāj (d. 160/776). Certainly, Successors like al-Zuhrī (d. 124/742) and even Companions had examined critically material they heard attributed to the Prophet ﷺ. Moreover, the critical opinions of Successors would inform later hadith critics. A formalized system of requiring isnāds and investigating them according to agreed conventions and through a set of technical terms, however, did not appear until the time of Mālik.

Step one: The isnād

The isnād, or ‘support,’ was the essential building-block of the hadith critical method. So essential would the isnād be to the Sunni science of hadith criticism that it became the veritable symbol of the ‘cult of authenticity’ that is Sunni Islam. One of the most oft-repeated slogans among hadith critics comes from the famous scholar Ibn al-Mubārak (d. 181/797), who said, “The isnād is part of religion; if not for the isnād, whoever wanted could say whatever they wanted. But if you ask them, ‘Who told you this?’ they cannot reply.” Al-Shāfiʿī provided a similarly famous declaration, “The person who seeks knowledge without an isnād, not asking “Where is this from?,” indeed, he is like a person gathering wood at night. He carries on his back a bundle of wood when there may be a viper in it that could bite him.” Sunnis thus understood the isnād as the prime means of defending the true teachings of the Prophet ﷺ against heretics as well as protection from subtle deviations that might slip into Muslims’ beliefs and practice.

The origins of the isnād were as commonsense as its function, beginning with the rise of hadith forgery. As the Successor Muhammad ibn Sīrīn (d. 110/729), a leading student of the Companion Anas ibn Mālik, explained:

In the early period no one would ask about the isnād. But when the Strife [most probably the Second Civil War, 680–692 CE] began, they would say “Name for us your sources” so that the People of the Sunnah (ahl al-sunnah) could be identified and their hadiths accepted, and the People of Heresy (ahl al-bidʿah) could be identified and their hadiths ignored.

In the milieu of the early Islamic period, simply demanding an isnād for reports attributed to the Prophet ﷺ was an excellent first line of defense against inauthentic material entering Muslim discourse. We can imagine the newly Muslim inhabitants of Kufa, still clinging to Christian or Zoroastrian lore, or even Bedouins eager to insinuate tribal Arab values into Islam, ascribing a saying to the Prophet as evidence for their ideas. If they provided no isnād at all, the reports would not enter the musnad collections of scholars like Abū Dāwūd al-Ṭayālisī (d. 204/820). The formative critic Shuʿba is quoted as saying, “All religious knowledge (ʿilm) which does not feature ‘he narrated to me’ or ‘he reported to me’ [the components of the isnād] is just vinegar and sprouts.”

Step two: Rating transmitters and establishing contiguous transmission

On their own, however, isnāds could not deter a determined forger. As we saw with the hadiths on human reason, an isnād could be made up or inauthentic material could simply be equipped with an isnād and then circulated. Moreover, merely requiring someone to provide a source for a hadith they cited did not tell you if that source was reliable. The second tier of criticism thus involved identifying the individuals who constituted isnāds, evaluating their reliability, and then determining if there were any risks that someone unreliable might also have played some part in transmitting the report.

1) Transmitter evaluation

A hadith transmitter was evaluated according to two criteria. First, his or her character, correct belief, and level of piety were scrutinized in order to determine if he or she was ‘upright’ (ʿadl). Second, and much more importantly, the transmitter’s corpus of reports and narration practices were evaluated to decide if he or she was ‘accurate’ (ḍābit).

Hadith transmitter criticism (known as al-jarḥ wa-al-taʿdīl, ‘impugning and approving’) and isnād evaluation began in full with the first generation of renowned hadith critics, that of Shuʿbah ibn al-Ḥajjāj, Mālik ibn Anas, Sufyān al-Thawrī, al-Layth ibn Saʿd, and Sufyān ibn ʿUyaynah, who flourished in the mid to late eighth century in the cities of Basra, Kufa, Fustat (modern-day Cairo), Mecca, and Medina (see Figure 2). These scholars began the process of collecting people’s hadith narrations and examining both their bodies of material and their characters to determine if the material they purveyed could be trusted. Mālik is the first scholar known to have used technical terms such as ‘thiqah’ (reliable) to describe these narrators, while Shuʿba’s evaluations did not utilize any specialized vocabulary.

The evaluations of this first great generation were studied and added to by their students, especially the two great Basran critics ʿAbd al-Raḥmān ibn Mahdī (d. 198/814) and Yahyá ibn Saʿīd al-Qaṭṭān (d. 198/813). The later analyst Shams al-Dīn al-Dhahabī notes that “whoever they both criticize, by God, rarely do you find that criticism refuted [by others], and whoever they both agree on as trustworthy, he is accepted as proof.” The critical methods and opinions of Ibn Mahdī and al-Qaṭṭān passed on to their three most respected students, who can be seen as the beginning of the heyday of Sunni hadith criticism: Ibn Ḥanbal (d. 241/855) and his friend Yahyá ibn Maʿīn (d. 233/848) in Baghdad and ʿAlī ibn al-Madīnī in Basra (d. 234/849). Their students refined hadith criticism into its most exact and lasting form: the ‘Two Shaykhs’ al-Bukhārī and Muslim, the two senior critics of Rayy (modern Tehran), Abū Zurʿah al-Rāzī (d. 264/878) and his friend Abū Ḥātim al-Rāzī (d. 277/890), as well as influential younger critics of that generation such as al-Nasāʾī (d. 303/916).

The 900s saw several generations of critics who reviewed and reassessed the judgments of these earlier scholars and also continued to evaluate those involved in the ongoing transmission of hadiths: Ibn Abī Ḥātim al-Rāzī (d. 327/938), Ibn ʿAdī (d. 365/975-6), Ibn Ḥibbān al-Bustī (d. 354/965), Abū al-Ḥasan al-Dāraquṭnī (d. 385/995), and al-Hākim al-Naysābūrī (d. 405/1014).

Although the apex and most active period of hadith transmitter criticism is usually considered to be the eighth to tenth centuries, subsequent generations of critics contributed to this science as well. Hadiths were still transmitted with full isnāds into the early 1200s, so it was possible until that time for previously unrated hadiths to be in circulation among transmitters. Master hadith scholars like al-Khaṭīb al-Baghdādī (d. 463/1071) and Ibn ʿAsākir (d. 571/1176) therefore continued to rate transmitters living in their times. Furthermore, they synthesized, reconciled, and reexamined existing opinions on earlier transmitters.

This reconsideration of earlier transmitters’ standing has, in fact, never really ended. If we look at al-Dhahabī’s list of the expert critics whose opinions should be heeded, we find that it continues until al-Dhahabī ’s own time in the 1300s. One of the most commanding critics in the Sunni hadith tradition, ‘the Hadith Master (al-ḥāfiẓ)’ Ibn Ḥajar al-ʿAsqalānī, died in 852/1449. Hadith transmitter criticism has continued until the modern day. This is possible because, as we shall see, determining if someone was reliable or not had little to do with any personal experience with their character, its flaws, or fine qualities. Ultimately, it was the analysis of the body of their transmissions for corroboration that determined their accuracy (ḍabt) and thus their station.

How would a hadith critic such as Shuʿbah, al-Bukhārī, or Ibn ʿAdī actually evaluate a transmitter? First, it was essential to know who this transmitter was. If one was presented with a hadith transmitted from ‘someone,’ ‘Aḥmad,’ or ‘a group of people in Medina,’ how could one evaluate the strength of its isnād? By the mid 800s it had become accepted convention among hadith critics that a person needed two well-known transmitters to identify him sufficiently, prove that he existed, and narrate hadiths from him in order to qualify for rating. Otherwise, the transmitter would be dismissed as ‘unknown’ (majhūl) and the report automatically considered unreliable.

Second, the critic would collect all the reports that the transmitter had narrated from various teachers and then analyze them for corroboration, a process known as ‘consideration' (iʿtibār). It was here that the musnad genre of hadith collection would be very useful, since they were organized not by subject matter but by narrators in the isnāds. But ultimately a critic would have to rely on a robust memory in order to recall all the different isnāds in which the transmitter in question played some part. For every hadith that the transmitter narrated from a certain teacher, the critic asks, “Did this teacher’s other students narrate this report too?” If the critic finds that, for all the teachers that the transmitter narrates from, his fellow students corroborated him for a very high percentage of his hadiths, then he is considered to be reliable in his transmissions. When asked what kind of transmitters should be abandoned as unreliable, Shuʿbah explained:

Someone who narrates excessively from well-known transmitters what these well-known transmitters do not recognize, his hadiths are cast aside. And if he makes a lot of mistakes, his hadiths are cast aside. And if he is accused of forgery (kādhib), his hadiths are cast aside. And if he narrates a hadith that is agreed upon as an error, and he does not hold himself accountable for that and reject the report, his hadiths are cast aside.

Muslim ibn al-Ḥajjāj describes the telltale signs of a weak hadith transmitter as someone who, “when his narrations are compared with those of people known for preservation [of hadith] and uprightness of character, his narrations do not concur with their narrations, or do so only rarely. If the majority of his hadiths are like that then he is rejected and not used in hadith.”

Early hadith critics understood very well that no one transmitter was immune from error. Below the level of master transmitters, Ibn Mahdī described a lesser type of narrator “who makes errors, but most of his hadiths are ṣaḥīḥ. This kind of person’s hadiths should not be abandoned, for if they were, all the people’s hadiths would disappear.”

Finally, the critic would examine the transmitter’s character, religious beliefs, and piety in order to determine his ‘uprightness’ (ʿadālah). Although later legal theorists would establish very formal requirements for someone to be declared ‘upright,’ such as the requirement widely accepted by Sunnis after the 1200s that the transmitter be “Muslim, of age, of sound mind, free of sinful behavior and defects in honor,” early hadith critics were actually very flexible with determining uprightness.

This is most evident in the issue of transmitters who espoused beliefs that Sunnis considered heretical, such as Shiism, belonging to the Kharijite sect, or a belief in free will (qadar). Although al-Shāfiʿī had declared that one could accept hadiths from transmitters regardless of their sectarian affiliations as long as they did not belong to certain Shiite sects that allowed lying, by the mid 900s scholars like Ibn Ḥibbān had declared a consensus among Sunni hadith critics that one could accept hadiths from any heretical transmitter provided he was not an extremist and did not actively try to convert others to his beliefs. In theory, this meant that one could accept hadiths from Shiite transmitters as long as they did not engage in virulently anti-Sunni practices such as cursing Abū Bakr or ʿUmar or transmit hadiths that seemed to preach the Shiite message.

In truth, however, early hadith critics did not follow these strictures. As the eighteenth-century Yemeni hadith analyst Ibn al-Amīr al-Ṣanʿānī (d. 1768) observed, later theorists had set up principles that did not apply to the realities of early hadith criticism. Al-Bukhārī, the most revered of all hadith critics, narrated two hadiths in his famous Ṣaḥīḥ through the extreme Kharijite ʿImrān ibn Ḥiṭṭān. In his Sahīh, Muslim narrated the hadith that “Only a believer loves ʿAlī, and only a hypocrite hates him” through the known Shiite transmitter ʿAdī ibn Thābit. As we can see, the two uncontested masters of Sunni hadith criticism could narrate hadiths that they considered authentic through extremists and heretics who proselytized for their cause.

The explanation for this lies in the priorities of the early hadith critics. Simply put, if a transmitter consistently and accurately passed on hadiths he had heard from the previous generation, hadith critics had little interest in his beliefs or practice. Ibn Maʿīn described the Shiite transmitter ʿAbd al- Raḥmān ibn Ṣāliḥ as “trustworthy, sincere, and Shiite, but who would rather fall from the sky than misrepresent half a word.” One prominent early hadith transmitter, Ismāʿīl ibn ʿUlayyah (d. 193/809), became so shamefully intoxicated on one occasion that he had to be carried home on a donkey. Yet he was a reliable transmitter, so his hadiths were accepted. Although later theorists of the hadith tradition would talk of the two pillars of reliability as ‘uprightness (ʿadālah) and accuracy (ḍabt),’ al-Sanʿānī rightly pointed out that one should reorder them ‘accuracy and uprightness,’ since the former greatly outweighed the latter.

Ultimately, Sunnis could not escape their dependency on the role of ‘non-Sunnis’ in hadith transmission. The early critic Ibn Saʿd (d. 230/845) notes how one Khālid al-Qaṭwānī was a staunch Shiite but that hadith scholars “wrote down his hadiths out of necessity.” Without such ‘heretics,’ critics knew that few hadiths would ever have been transmitted.

Guaranteeing the transmitter’s ‘uprightness’ (ʿadālah), however, did have an important function. Regardless of a transmitter’s accuracy, if they were known to have intentionally misrepresented the Prophet ﷺ or forged a hadith, then they could not be trusted. Sulaymān ibn Dāwūd al-Shādhakūnī (d. 234/848-9), for example, was considered to have the most prodigious memory of hadiths in his time and one of the biggest hadith corpora. Yet he was known to have lied about hadiths and altered them to fit certain situations, so he was excluded from transmission. Al-Shādhakūnī was so untrustworthy that when he awed a gathering by claiming that he knew a hadith from Rayy that Abū Zurʿah al-Rāzī did not know, people believed that he had just made it up on the spot to impress them.

Although in the eighth and ninth centuries each hadith critic used slightly different and sometimes shifting terms to describe a transmitter’s level of reliability, by the early tenth century a conventional jargon had emerged. Ibn Abī Ḥātim al-Rāzī (d. 327/938) lists the levels as:

1. ‘Reliable’ (thiqah, mutqin, thabt) transmitter’s hadiths can be used as proof in legal scholarship with no hesitation
2. ‘Sincere’ (sadūq, lā baʾs bihi) transmitter’s hadiths are recorded and can be taken as proof if bolstered or corroborated
3. ‘Venerable’ (shaykh) transmitter’s hadiths are used for identifying corroboration depending on strength
4. ‘Righteous’ (ṣāliḥ) transmitter’s hadiths are used for identifying corroboration depending on strength
5. ‘Lenient on hadith’ (layyin al-ḥadīth) transmitter’s hadiths can be used for identifying corroboration
6. ‘Not strong’ (laysa bi-qawī) transmitter’s hadiths can still be used for identifying corroboration
7. ‘Weak’ (daʿīf) transmitter’s hadiths can be used to corroborate but not on their own
8. 'Liar, abandoned’ (matrūk al-ḥadīth, dhāhib al-ḥadīth, kadhdhāb) transmitter’s hadiths are not used at all.

Books of transmitter criticism

Hadith transmitter criticism often took place in discussion sessions among critics or with their students, but its results were set down by master critics in dictionaries of transmitter evaluation (kutub al-rijāl). Early works include the Ṭabaqāt al-kubrá (The Great Book of Generations) of Ibn Saʿd (d. 230/845), the Aḥwāl al-rijāl (Conditions of the Transmitters) of al-Jūzajānī (d. 259/873), the massive ‘Great History (al-Tārīkh al-kabīr)’ of al-Bukhārī, and the Jarḥ wa-al-taʿdīl of Ibn Abī Ḥātim al-Rāzī. Some books focused specifically on discussing transmitters whom the author felt were reliable; these included al-ʿIjlī’s (d. 261/875) Tārīkh al-thiqāt and Ibn Ḥibbān’s Kitāb al-thiqāt. Voluminous books were devoted to listing and discussing weak transmitters as well. The most important are the Kitāb al-duʿafāʾ al-kabīr of al-Bukhārī (now lost), the Kāmil fī duʿafāʾ al-rijāl of Ibn ʿAdī and Ibn Hibbān’s Kitāb al-majrūḥīn. Such works presented critics’ opinions of a transmitter along with a selection of the unacceptable narrations that they transmitted. Because they consistently evaluated the reliability of personalities they mention, local histories like al-Khaṭīb’s History of Baghdad are also works of transmitter criticism.

In the period of consolidation and analysis from the 1300s to the 1600s, later critics amalgamated and digested these earlier works of hadith criticism. ʿAbd al-Ghanī al-Maqdisī (d. 600/1203) wrote his al-Kamāl fī maʿrifat asmāʾ al-rijāl (The Perfection in Knowing the Names of Transmitters), presenting earlier descriptions and evaluations of all the transmitters in the Six Books. Jamāl al-Dīn al-Mizzī (d. 742/1341) added to this work and further analyzed the ratings of the transmitters within the Six Books in his Tahdhīb al-kamāl (The Refinement of Perfection), published today in thirty-five volumes. Ibn Ḥajar al-ʿAsqalānī produced an abridgment of this work with his own comments entitled Tahdhīb al-tahdhīb (The Refinement of the Refinement). Scholars like the Egyptian Ibn al-Mulaqqin (d. 804/1401) added the transmitters found in other hadith collections such as the Musnads of Ibn Ḥanbal and al-Shāfiʿī as well as the Ṣaḥīḥ of Ibn Khuzaymah and the Mustadrak of al-Ḥākim to expanded versions of al-Mizzī’s book. The Ḥanafī scholar of Cairo, Badr al-Dīn al-ʿAynī (d. 855/1451), devoted a rijāl work to the transmitters in al-Ṭaḥāwī’s collections.

Other later analysts focused on the subject of weak transmitters. Shams al-Dīn al-Dhahabī wrote his masterful Mīzān al-iʿtidāl fī naqd al-rijāl (The Fair Scale for Criticizing Transmitters), collecting all the information on any transmitter impugned by earlier figures. Ibn Ḥajar added his own comments in a revision of this work, Lisān al-mīzān (The Pointer of the Scale).

As we saw in the last chapter, the isnāds to hadith books could affect the reliability of hadiths in them, especially during the ninth and tenth centuries. Scholars like Ibn Nuqṭah of Baghdad (d. 629/1231) therefore wrote books of transmitter criticism addressing the people who conveyed books from their authors. Ibn Nuqṭah’s al-Taqyīd fī maʿrifat ruwāt al-sunan wa-al-masānīd and Abū ʿAlāʾ al-Fāsī’s (d. 1770) addendum to that book are examples of this genre.

Reconciling disagreements among critics

With the plethora of transmitter critics from the eighth century on, how was a later critic or analyst supposed to know whose opinion to take on the reliability of a narrator or a hadith? Ibn Isḥāq (d. 150/767), for example, the author of the famous biography of the Prophet ﷺ, was a very controversial figure. Mālik, Ibn al-Qaṭṭān, Ibn Ḥanbal, and others considered him highly unreliable because he accepted hadiths from questionable narrators as well as Christians and Jews. But Shuʿbah felt he was impeccably reliable, ʿAlī ibn al-Madīnī named him one of the pivots of hadith transmission in his age, and all the Six Books relied on him as a narrator (though the Ṣaḥīḥayn of al-Bukhārī and Muslim only use him for rare backup narrations). Certainly, this created a great potential for disagreement over the reliability of transmitters and, hence, of hadiths themselves.

To a certain extent, such disagreement was the inevitable result of the complicated careers of transmitters and the contrasting critical thresholds of the many individual analysts examining them and their reports. One critic could change his mind about a transmitter, as al-Bukhārī did when he reduced Muhammad ibn Ḥumayd al-Rāzī’s rating from ‘good’ to ‘weak.’ As the hadith scholar al-Ismāʿīlī (d. 371/981) noted, critics often rated transmitters in relation to certain of their teachers. So a critic might describe a transmitter positively in one place and negatively in another.

In general, however, later analysts erred on the side of caution and operated on the principle that ‘criticism supersedes approval provided that the reason for the criticism is provided.’ There were limits to this, however. Scholars who had personal vendettas against one another—Mālik’s criticism of Ibn Isḥāq was the result of a well-documented personal feud between them—were not accepted as fair critics of one another.

Later analysts were often aware of such issues and took earlier critics’ idiosyncrasies and personal leanings into consideration. Al-Jūzajānī was known to have a vehement dislike for Shiism, so any rejection by him of a transmitter as ‘a heretical Shiite’ was probably an overstatement. If he approved of a transmitter, however, it meant that he was certainly free of any Shiite tendencies. Abū Ḥātim al-Rāzī was well known as a very stringent critic—even the seminal legal and hadith scholar al-Shāfiʿī had only merited a ‘sincere (ṣadūq)’ rating with him. Ibn Maʿīn was very harsh—once calling a narrator who criticized a Companion a… person who had improper relations with his own mother—so his approval carried great weight. Ibn ʿAdī was generally very objective. He would limit his evaluations to strict examinations of transmitters’ hadiths for corroboration or its absence. As a result, he would often overturn the disapproval of an earlier critic with a comment such as “I have not found uncorroborated reports among his hadiths.”

The standing of the Companions

The Companions of the Prophet ﷺ achieved a unique place in the worldview of Sunni hadith critics. Although some early historians and transmitters like al-Wāqidī (d. 207/822–3) only considered those who reached adulthood during the lifetime of the Prophet to be Companions, the definition that became accepted by Sunnis was much less strict. As al-Bukhārī notes in his Ṣaḥīḥ, a Companion is anyone who saw the Prophet, even for a moment, while a believer and who then died as a Muslim.

This had tremendous consequences for hadith transmission, for by 900 CE Sunnis considered that all the Companions of the Prophet were automatically ‘upright (ʿadl).’ This belief was based on Qur’anic verses such as “You are the best community brought out for humanity” (kuntum khayr ummah ukhrijat lil-nās) (Qur’an 3:110) and Prophetic hadiths such as “The best of generations is the one in which I was sent, then that which follows, then that which follows.” In effect, then, the first generation of hadith transmitters was beyond criticism. In fact, the famous ninth-century hadith critic Abū Zurʿah al-Rāzī stated that anyone who criticized a Companion was a heretic.

Later analysts would refine this understanding of the Companions’ uprightness. As Ibn Taymiyyah (d. 728/1328) explained, the Companions were not perfect—Mughīrah ibn Shuʿbah had lied, and Walīd ibn ʿUqbah was a known drunkard. But none had ever lied about the Prophet ﷺ. Many Sunni scholars have thus understood uprightness as meaning that the Companions’ exposure to the tremendous spiritual charisma of the Prophet prevented them from lying about him but did not prevent other sins.

It is no surprise, then, that Sunni hadith scholars strove to identify who was a Companion. ʿAlī ibn al-Madīnī (d. 234/838) wrote an early work (now lost) listing them, to be followed by Ibn Qāniʿ (d. 351/962), Abū Nuʿaym al-Iṣbahānī, and others. Ibn Ḥajar al-ʿAsqalānī’s Iṣābah fī maʿrifat al-ṣaḥābah is the most widely cited biographical dictionary of the Companions. There was great disagreement over the actual number of Companions: al-Shāfiʿī estimated their number at sixty thousand, Abū Zurʿah al-Rāzī at over a hundred thousand. In his biographical dictionary of Companions, Ibn Ḥajar listed approximately twelve thousand three hundred. On a practical level, the Companions who actually played a noticeable role in hadith transmission were far fewer: the Six Books include hadiths from only 962 Companions.

The Sunni critics’ view of the Companions was both ideologically driven and practical. Islam was built on the idea that the Companions of the Prophet ﷺ had inherited his authority and passed on his teachings reliably. In that sense, as a group they were above reproach. In terms of hadith criticism, however, the critics’ reach did not extend far enough back to apply the rules of transmitter criticism to the Companions. The earliest critic, al-Zuhrī, had met only the youngest of the Companions, and his hadith criticism mostly addressed the reports he heard from other Successors. Al-Zuhrī, Mālik, and Shuʿbah had direct experience with the Successors, but they had no real way to evaluate the uprightness or accuracy of Companions. In a sense, reports such as Aisha’s aforementioned rejection of hadiths for content reasons represent vestiges of hadith criticism from the Companion generation. 

The chicken and the egg: Who made the early experts experts?

The names of the early generations of master hadith critics (Figure 2) overlap to a large extent with those of major hadith transmitters. So did just transmitting a vast number of hadiths make a person a reliable hadith transmitter or an expert critic? The answer seems to be no—just because one was a major transmitter did not mean that one was reliable. Ibn Isḥāq was an essential pivot of hadith transmission in Medina, but it became clear to many critics even in his own lifetime that he was not at all discriminating in what he transmitted. Mālik, on the other hand, only transmitted from two people (ʿAbd al-Karīm ibn Abī al-Mukhāriq and ʿAtāʾ al-Khurāsānī) that he (and later critics) did not feel were reliable (thiqah). Later critics also distinguished between an early critic/transmitter’s own transmissions and his evaluations of others. Al-Zuhrī’s opinions carried great influence, but later critics all agreed that his mursal hadiths (see below for a discussion of this term) were too unreliable to use. The great critic Sufyān al-Thawrī regularly narrated hadiths that others considered unreliable, whereas when Shuʿbah transmitted a hadith, it was understood that he believed it was authentic.

In a similar vein, in the formative period of Sunni Islam in the ninth century, did hadith scholars such as Ibn Ḥanbal decide which early transmitters to accept based on their Sunni beliefs? Was Sunni hadith criticism just a tool for excluding non-Sunnis? The answers to these questions are certainly ‘no,’ since, as we have seen, Sunni critics regularly accepted the hadiths of people whose beliefs they considered anathema. Beyond merely accepting non-Sunnis as transmitters of hadiths, Sunnis even accepted one as a hadith critic. Despite his fervent Shiism, Ibn ʿUqdah (d. 332/944) was listed by staunch Sunnis like al-Dhahabī as “the oceanic hadith scholar,” whose criticisms of transmitters and narrations carried great weight.

2) Contiguity of transmission (al-ittiṣāl)

Evaluating the sources of a hadith was of little use, however, if a critic could not be sure who these sources were. If one transmitter had never actually met the person from whom they quoted the hadith, or if it was known that he had not heard that hadith from his teacher, then who was the intermediary? With no way to guarantee that intermediary’s reliability, there were endless possibilities for what sort of deviation or forgery could have occurred. Establishing that a hadith had been transmitted by a contiguous, unbroken isnād from the Prophet ﷺ was thus as crucial as transmitter reliability for determining the authenticity of a hadith. If it could not be established that the people in the isnād had heard from one another, then hadith critics considered the chain of transmission broken (munqaṭiʿ) and thus unreliable.

In order to determine if an isnād was ‘contiguous’ (muttaṣil), hadith critics attempted to identify all the people from whom a narrator had heard hadiths. If a transmitter was not a known liar, then one could infer this from his saying “So-and-so narrated to me” (ḥaddathanī), “So-and-so reported to us” (akhbaranā), or “I heard from so-and-so” (samiʿtu min...). Other phrases for transmission did not necessarily indicate direct transmission. “According to” (ʿan) could mean that someone had heard a hadith directly from the person in question or not. In addition to looking at this terminology, a critic would compare the death date of the teacher with the age of the student and investigate the possibility that they were in the same place at the same time.

Because establishing contiguous transmission was so important, by the mid 700s transmitters had become very serious about specifying exactly how hadith transmission occurred. The most accurate forms of direct transmission were either reading a teacher’s hadiths back to him (often indicated by the phrase “he reported to us” (akhbaranā’)) or listening to the teacher read his hadiths (often indicated by “he narrated to us” (ḥaddathanā’)). If a teacher gave a student his books of hadiths to copy, this was termed “handing over” (munāwalah). Although there was debate over whether reading hadiths to a teacher or hearing them read was more accurate, all scholars acknowledged that ‘handing over’ and liberal ‘permission to transmit’ were the most tenuous forms of transmission. Reading a book with no transmission from the teacher at all (“finding” (wijādah)) inspired no confidence at all.

Transmitters fretted over these forms of narration and often debated the proper terminology. The Ḥanafī al-Ṭaḥāwī (d. 321/933) wrote a short treatise on how the technical terms ‘akhbaranā’ and ‘ḥaddathanā’ actually meant the same thing (also the opinion of the majority of scholars). When al-Awzāʿī gave a book of hadiths to a student in an act of ‘handing over,’ the student asked, “About this book, do I say ‘ḥaddathanī’?” Al-Awzāʿī replied, :”If I narrated it directly to you, then say that.” The student inquired, “So do I say ‘akhbaranī’?” Al-Awzāʿī replied that no, he should say “al-Awzāʿī said” or “according to al-Awzāʿī.”

Not all critics agreed on the requirements for a contiguous isnād. There was disagreement over whether the phrase “according to” (‘an ) should be interpreted as an indication of direct transmission or not. Muslim ibn al-Ḥajjāj claimed that the great hadith critics had all accepted ʿan as indicating direct transmission provided that the two people involved were contemporaries and that it was likely that they had met one another. Others, like Ibn ʿAbd al-Barr (d. 463/1070) and al-Khaṭīb al-Baghdādī, claimed that hadith critics had agreed that one needed proof that the two transmitters had actually met at least once. 

Obfuscation in transmission (tadlīs)

Critics of the eighth, ninth, and early tenth centuries often attempted to be more exact than just establishing if two transmitters had met. They sought to determine exactly which hadiths certain transmitters had heard from their teachers. Shuʿba thus studied the hadiths of his teacher Qatādah until he found that he had only heard three from his teacher Abū al-ʿĀliyah. This was especially important in the case of tadlīs, or obfuscation in transmission. Tadlīs occurred when a transmitter cited an isnād in an ambiguous manner, such as saying “so-and-so said,” implying that he had heard the hadith directly from the person when in fact he was omitting his immediate source for the hadith. Transmitters might hide their immediate source because he or she was considered unreliable or espoused beliefs unacceptable in Sunni Islam. Tadlīs did not always occur for insidious reasons. If a student had to leave a dictation session to answer nature’s call, for example, he would hear the hadiths that he had missed from a classmate. When narrating those hadiths, however, he might leave out the classmate’s name and simply say “Teacher so-and-so said.” Because tadlīs was often innocuous, very few transmitters were totally innocent of it. Only Shuʿbah ibn al-Ḥajjāj was known to never lapse into it.

Identifying tadlīs was a primary concern of critics in the eighth century and beyond. By interrogating a transmitter a critic could determine whom he omitted from isnāds in instances of tadlīs. Transmitters like Sufyān ibn ʿUyaynah, who only omitted the names of reliable figures, could be trusted even when doing tadlīs. Others who often omitted the names of weak narrators, like Ibn Isḥāq, could not be relied upon unless they specified direct transmission. Al-Khaṭīb al-Baghdādī and Ibn Ḥajar both wrote books discussing tadlīs and those accused of it.

Mursal hadiths

Similar to tadlīs was the phenomenon of mursal hadiths, or instances in which someone quoted the Prophet ﷺ without ever having met him. If a Successor or an early scholar like Mālik said “the Prophet said,” this was clearly an incomplete isnād since Mālik never met the Prophet ﷺ. Mursal hadiths occurred because, especially in the first few generations of Muslims, scholars were not obsessive about providing detailed isnāds for every report all the time. Al-Zuhrī, Mālik, or Abū Ḥanīfah might quote the Prophet while discussing a legal issue informally without bothering to provide an isnād.

When such mursal hadiths were recorded in muṣannaf works like the Muwaṭṭaʾ or the legal responses of Abū Ḥanīfah, however, they presented a problem for later hadith critics. How should they be treated? Because mursal hadiths had incomplete isnāds and one could not be sure from whom a Successor was narrating, mursals were almost always considered unreliable by hadith critics. After extensive research on the mursal reports of certain early transmitters, however, and attempts to find counterparts to them with full isnāds, critics approved of certain transmitters’ mursal hadiths. Al-Shāfiʿī concluded that the mursals of the Successor Saʿīd ibn al-Musayyab (d. 94/713) were reliable because the source he omitted, his father-in-law Abū Hurayrah, was the most knowledgeable Companion about hadiths. Critics debated the reliability of al-Ḥasan al-Baṣrī’s mursal hadiths—his contemporary Ibn Sīrīn said that al-Ḥasan was totally uncritical about his hadith sources, so his mursals were useless. Yaḥyá al-Qaṭṭān said that he had studied all of al-Ḥasan’s mursals and found versions with full isnāds for all but two of them. Ibn Abī Ḥātim al-Rāzī composed a whole book entitled Kitāb al-marāsīl (The Book of Mursals) in an attempt to determine which Successors had heard hadiths from which Companions.

Step three: Finding corroboration for the hadith

Corroboration had played a central role in determining the reliability of a transmitter—if he narrated hadiths that other students of his source did not, then his reliability was questioned. But a forger could still simply take an isnād of a respected transmitter and attach it to a freshly concocted hadith. The third and final step in hadith criticism thus involved looking for corroboration for the hadith itself.

Corroboration took two general forms (see Figure 3). Since a ‘hadith’ was generally associated with the Companion who narrated it, another version of the same Prophetic tradition transmitted by a second Companion or an instance of the Prophet ﷺ saying something similar on another occasion were both considered corroboration for a hadith. Such a report was termed a “witness” (shāhid). When one transmitter corroborated the report related by another transmitter that they had both heard from a common source, this was termed a “parallelism” (mutābaʿah). Hadith scholars described these two forms of corroboration with the aphorism “parallelism bolsters the narration; a witness bolsters the tradition.” A witness report need not be exactly the same tradition as the hadith it supports. Even a report with a different wording but the same meaning corroborated the fact that the Prophet ﷺ had expressed a certain idea or sentiment. Parallelisms solidified the reliability of a particular narration of a hadith.

A famous tenth-century hadith critic, Ibn Hibbān, describes the process of searching for corroboration (called iʿtibār, ‘consideration’) thus:

Let us say we come across [the transmitter] Ḥammād ibn Salamah, and we see that he has narrated a report from Ayyūb [al-Sakhtiyānī], from Ibn Sīrīn, from Abū Hurayrah, from the Prophet ﷺ, but we do not find that report from anyone else from the students of Ayyūb. What is required of us now is to refrain momentarily from criticizing Ḥammād, and to consider what his contemporaries narrated. So we must start by looking at this report: Did Ḥammād’s students in general narrate it from him, or just one of them? If it is the case that his students narrated it from him, then it has been established that Ḥammād really did narrate that report, even if that comes through a weak narrator from him, because that narration is added to the first narration from Ḥammād. So if it has been established correctly that Ḥammād narrated a report from Ayyūb that is not corroborated by others, again we must pause. For it does not follow automatically that there is some weakness here, but rather we must ask: Did any of the reliable transmitters (thiqāt) narrate this report from Ibn Sīrīn other than Ayyūb? If we find one, then it has been established that the report has some basis (aṣl yarjiʿu ilayhi). If not, then we must ask: Did anyone from among the reliable transmitters narrate this report from Abū Hurayrah other than Ibn Sīrīn? If such a narration is found, then it has been established that the report has a basis (aṣl). If not, we ask: Did anyone narrate this report from the Prophet ﷺ other than Abū Hurayrah? If so, then it has been established correctly that the report has some basis. But when that is not the case, and the report contradicts the compilations of these three [people at three levels in the isnād], then it is established without a doubt that the report is forged, and that the lone person who narrated it forged it.

As Ibn Ḥibbān describes, if a report is not corroborated at any one level of the isnād, then the reliability of that transmitter’s narration from his source is dubious. If the report is uncorroborated at all levels of the isnād, then it is almost certainly totally baseless. If a report was not corroborated either at some level of the isnād or from the Prophet ﷺ in general, early hadith critics deemed it “unknown/unacceptable” (munkar).

Here we see that Muslim critics worked backwards in time when authenticating hadiths. What probably first occurs to readers today is that an isnād ‘starts’ with the Prophet and ‘ends’ when the hadith is recorded in a book. But this assumes that the hadith actually existed in the time of the Prophet and that we are merely tracing how it came to us. For a Muslim hadith critic, a hadith was at first just an unverified claim; its isnād began with the person who told him the hadith. It only extended backward in time when the critic verified each link in the isnād, step by step, until it “reached” (waṣl) the Prophet ﷺ.

Of course, this process of demanding corroboration took context into consideration. As Muslim ibn al-Ḥajjāj informs us, “If it has been established that your hadith corpus agrees with those of the other reliable narrators, then narrating some uncorroborated material is acceptable.” If a transmitter studied with a certain teacher for ten years, then it is not surprising that he might narrate a selection of hadiths from his teacher that students who only studied with him for six months did not recount. The great critic Abū Ḥātim al-Rāzī was asked to criticize ʿAbd Allāh ibn Ṣāliḥ, the secretary of Layth ibn Saʿd, for having narrated uncorroborated hadiths from Layth. Abū Ḥātim replied sarcastically, “You ask me this about the closest person to Layth, who was with him on voyages and at home and spent much time alone with him?” But, Muslim continues, if some lesser known transmitter narrated a hadith from a prolific hadith scholar like al-Zuhrī whose numerous and respected students did not recognize that hadith, then that report would be automatically declared “unacceptable” (munkar).

Like our modern investigative reporter’s source, however, a transmitter could earn such a level of confidence in the eyes of critics that he could narrate uncorroborated reports without arousing concern. Critics like al-Bukhārī and Ibn ʿAdī had examined the hadiths of master transmitters like al-Zuhrī, Mālik, Ibn al-Mubārak or Qutaybah b. Saʿīd and found that they were corroborated to such a great extent that they could be relied upon for a number of uncorroborated hadiths as well. These figures were so central to hadith transmission in general that if anyone were to have heard a rare hadith, it would be them. An uncorroborated hadith narrated by an isnād of such pillars was known as “an authentic rare” (ṣaḥīḥ gharīb) hadith. The hadith of Mālik al-Zuhrī Anas that the Prophet entered Mecca upon its conquest with a mail helmet on his head and ordered the killing of Ibn Khaṭal, an infamous enemy of Islam, was known only by this isnād. Because this hadith was narrated by transmitters whose collections of hadiths were vaster than almost any other people of their time, this hadith was considered authentic even though it was uncorroborated. 

Conversely, less stellar figures inspired no such confidence. As al-Tirmidhī explained, “Anyone from whom a hadith is narrated who is accused [of poor performance in hadith] or is criticized as weak in hadiths for his lack of carefulness and numerous mistakes, if that hadith is only known through that narration, it cannot be used as proof.” So the hadith narrated by the lone isnād of Nāṣiḥ al-ʿAjamī, from Simāk ibn Ḥarb, from Jābir ibn Samurah, from the Prophet ﷺ: “For a man to teach his child proper manners is better than to give a whole bushel in charity” (laʾan yuʾaddiba al-rajul waladahu khayr min an yataṣaddaqa bi-ṣāʿ) was considered unacceptable (munkar) because neither Nāṣiḥ nor Simāk were consistently reliable transmitters.

Even when an isnād looked perfect, early hadith critics did not completely ignore the need for comparing it with other narrations of the report. As the eleventh-century critic al-Khalīlī (d. 446/1054) warned, “Even if a hadith is provided to you with an isnād from al-Zuhrī or another one of the masters, do not declare it authentic merely because of that isnād, for even a reliable transmitter (thiqah) can err.” By comparing different versions of the same hadith, critics could uncover flaws, known as ʿilal, which might have evaded the best transmitter. Such flaws included one narration of a hadith adding additional words into the text of the report that were not found in more reliable versions. A very common flaw was that one narrator would confuse a Companion’s or Successor’s statement with a Prophetic hadith. The great ʿilal critic of Baghdad, al-Dāraquṭnī, found such an error in Muslim’s famous Ṣaḥīḥ. By examining all the narrations of a report describing how God will grant the believers a vision of Himself on the Day of Judgment, al-Dāraquṭnī concluded that these were actually the words of the Successor ʿAbd al-Raḥmān Ibn Abī Laylá (d. 82/701–2) and not of the Prophet ﷺ himself.

To uncover these ʿilal, a critic would gather all the narrations of a hadith and attempt to determine which ones were the most reliable. If the majority of respected transmitters, for example, reported that a certain saying was the statement of a Companion, even one strong isnād tracing that report back to the Prophet ﷺ would be considered a mistake.

This advanced level of seeking out corroboration and comparing narrations was set down in books of ʿilal, a genre that flourished in the ninth and tenth centuries. The ʿilal works of ʿAlī ibn al-Madīnī, Ibn Ḥanbal, and Ibn Abī Ḥātim al-Rāzī were very famous, but the massive ʿilal book of al-Dāraqutnī, published in eleven volumes, dwarfs them all. After the 1000s, ʿilal books became rare, and only unusually competent later critics like the Moroccan Ibn al-Qaṭṭān al-Fāsī (d. 628/1231) or Ibn al-Jawzī (d. 597/1201) produced them. ʿIlal criticism was only possible for critics in the early period when hadiths were still narrated by full isnāds and critics had access to reams of notes from dictation sessions holding versions of reports that may not have survived into later times. As al-Suyūṭī admitted, by the 1400s hadith critics did not have the vast array of muṣannafs, hadith notebooks, and dictation sessions available to a scholar like al-Dāraquṭnī. Such later scholars could only judge hadiths based on material they received from earlier critics.

When we think of how one should evaluate the reliability of things we hear, we focus on their content as much as their source. Even the most trustworthy source would arouse suspicion if he announced that aliens had landed in his backyard. Yet when we thumb through books of transmitter criticism or ʿilal, one of the most obvious characteristics of early hadith criticism is that early scholars almost never discussed the contents of hadith, let alone explicitly rejected a hadith because its meaning was unacceptable. Why is this?

Certainly, the esteem in which Muslims held Muhammad ﷺ and their belief that God spoke to him of the distant past and events to come affected their approach to criticizing hadiths. Unlike a modern person skeptically dismissing the sayings of a television psychic, a Muslim critic would not declare a report attributed to the Prophet ﷺ to be a forgery simply because it described something that average people could not know.

Nonetheless, we know that early critics like al-Bukhārī and Muslim were willing and able to reject a hadith because they found its contents inherently flawed. In his entry on the transmitter ʿAwn ibn  ʿUmārah al-Qaysī in his ‘Great Book of Weak Transmitters,’ al-Bukhārī noted that one of the unacceptable hadiths he narrated was “The signs of the Day of Judgment are after the year 200/815.” Al-Bukhārī rejects the hadith because “these two hundred years have passed, and none of these signs have appeared.” In another work on transmitters, al-Bukhārī criticizes Muhammad ibn Fadāʾ because he narrated the hadith “The Prophet forbade breaking apart Muslim coins in circulation.” Al-Bukhārī notes that Muslims did not mint coins until early Umayyad times; “they did not exist at the time of the Prophet.” Muslim bin al-Ḥajjāj rejects a hadith saying that there are five chapters of the Qur’an that are the equivalent of one-fourth of the holy book—a total of five-fourths. He calls this logical contradiction “reprehensible, and it is not conceivable that its meaning is correct.” But why were such instances of content criticism so rare?

To answer this question, we have to remember that Sunni hadith criticism emerged in the context of intense ideological struggle between the ahl al-ḥadīth and the school of early Muslim rationalists, known as the Muʿtazila. For the Muʿtazila, the only sources on which one could rely to interpret properly Islamic law and dogma were the Qur’an, reports from the Prophet ﷺ that were so well-known they could not possibly be forged, and human reason (ʿaql). In order to know if any hadith was authentically from the Prophet, Muʿtazilite scholars like Abū al-Qāsim al-Balkhī (d. 319/931) believed that it had to agree with the Qur’an and reason.

For Muʿtazilites, the idea that one could examine the isnād of the hadith to know if it was reliable or not was preposterous. The Muʿtazilite master Abū ʿAlī al-Jubbāʾī (d. 303/915–16) was once asked to evaluate two hadiths narrated through the same isnād. He declared the first hadith authentic but rejected the second as false. When a surprised student asked al-Jubbāʾī, “Two hadiths with the same isnād, you authenticate one and reject the other?,” al-Jubbāʾī replied that the second one could not be the words of the Prophet ﷺ because “the Qur’an demonstrates its falsity, as does the consensus of the Muslims and the evidence of reason.”

The ahl al-ḥadīth’s understanding of man’s relationship to religion was the converse. Only by submitting oneself completely to the uncorrupted ways of the Prophet ﷺ and early Muslim community as transmitted through the isnād could one truly obey God and His Messenger. Unlike the Muʿtazilah, whom they saw as arrogantly glorifying human reason, or the ahl al-raʾy, whom they viewed as rejecting or accepting hadiths arbitrarily when it suited their legal opinion, the ahl al-ḥadīth perceived themselves as “cultivating the ways of the Messenger, fending off heretical innovation and lies from revealed knowledge.” It was not man’s right to question the revealed religion that the Prophet ﷺ brought and that was preserved through the isnād. As al-Zuhrī expressed, “From God comes the message; upon the Messenger of God is its delivery; and upon us is submission.” We thus find the Companion ʿImrān ibn Ḥusayn (d. 52/672) instructing new Muslims that the Prophet ﷺ had said, “Whoever is grieved for excessively [by his family] will be punished [for that]” (man yunāhu ʿalayhi yuʿadhdhab). When a person questioned the reasonableness of this notion, ʿImrān replied, “The Messenger of God has spoken the truth, and you have disbelieved!” A defender of the ahl al-ḥadīth against the Muʿtazilah, Ibn Qutaybah (d. 276/889) states:

We do not resort except to that to which the Messenger of God resorted. And we do not reject what has been transmitted authentically from him because it does not accord with our conjectures or seem correct to reason... we hope that in this lies the path to salvation and escape from the baseless whims of heresy.

But we know from the examples above that early Sunni hadith critics did note problems in the meanings of certain hadiths. Human reason cannot simply be switched off. Nor should it be, since Abraham had rejected idolatry and embraced the worship of the Creator of the Heavens and the Earth by using reason to observe nature and ponder what God must be (Qur’an 6:76-9).  

In the context of their debate with the Mu‘tazila, however, it is clear why the ahl al-ḥadīth could not criticize the meaning of hadiths openly. The whole purpose of the isnād was to guarantee that the Prophet ﷺ said something without relying on man’s flawed reason. If hadith critics admitted that a hadith could have an authentic isnād but still be a forgery because its meaning was unacceptable, then they would be admitting that their rationalist opponents were correct. Hadith critics dealt with this by assuming that a problem in the meaning of a hadith was really a symptom of a flaw in the isnād. If you could not have a strong isnād with a forged report, then any problem in the meaning of a hadith must mean that there was a problem in the isnād. When ahl al-ḥadīth critics like al-Bukhārī came across a hadith whose meaning they found unacceptable, they examined the isnād to find how the error occurred and listed the hadith in the biography of that transmitter as evidence of his weakness. Ibn ʿAdī often states that the questionable hadiths that a certain transmitter narrates “demonstrate that he is unreliable.”

Because early hadith criticism was so openly focused on the isnād as the primary means of authentication, it was very often difficult to tell when a critic was rejecting a whole Prophetic tradition or just one narration of that hadith. The term “unacceptable” (munkar) for a hadith could mean that this version of the hadith narrated through a certain isnād was unreliable but other authentic versions existed, or that the tradition was entirely forged. Another phrase used to reject a hadith, “it has no basis” (laysa lahu aṣl), could mean that the hadith had no basis from that transmitter (but was well established from others) or that that particular tradition was baseless in general. But even concluding that the terms munkar or lā aṣl lahu denoted ‘forged’ does not necessarily mean that the critic found the meaning of the hadith in question unacceptable. As Ibn ʿAbd al-Barr (d. 463/1070) explained, “How many hadiths are there with a weak isnād but a correct meaning?” Al-Tirmidhī notes that Yaḥyá al-Qaṭṭān had declared the following hadith narrated by Anas to be munkar: “A man said, ‘O Messenger of God, should I tie up [the camel] and trust in God or leave it free and trust in God?’’ The Prophet ﷺ said, ‘Tie it up and trust in God.’” Al-Tirmidhī adds that this report was totally baseless from Anas, “but its likes have been narrated from another Companion ʿAmr ibn Umayyah al-Ḍamrī, from the Prophet.”

Starting in the late 1000s, however, as the Muʿtazilite rationalist threat faded from view and Sunni Islam emerged triumphant, hadith critics began writing books that rejected whole Prophetic traditions, often because their meanings were unacceptable. These books were known as works of mawdūʿāt, which listed ‘mawdūʿ,’ or ‘forged’ hadiths. The earliest known mawdūʿāt book, unfortunately lost to us, was that of Abū Saʿīd al-Naqqāsh al-Iṣbahānī (d. 414/1023). The earliest surviving one is the Tadhkirat al-mawḍūʿāt of Muhammad ibn Ṭāhir al-Maqdisī (d. 507/1113). Perhaps the most famous mawḍūʿāt work is the huge Kitāb al-mawḍūʿāt of Ibn al-Jawzī (d. 597/1201). Mawḍūʿāt books flourished in later Islamic times, with well-known works including the Aḥādīth al-daʿīfah of Ibn Taymiyyah (d. 728/1328), the al-Laʾālī al-masnūʿah of al-Suyūtī, the Asrār al-marfūʿah of Mullā ʿAlī Qārī (d. 1014/1606), the Fawāʾid al-majmūʿah of the Yemeni Muhammad al-Shawkānī (d. 1834), and the Kitāb al-āthār al-marfūʿa of the Indian ʿAbd al-Ḥayy al-Laknawī (d. 1886-7). Some of these scholars wrote books on forged hadiths designed to be useful references for non-experts. ʿUmar ibn Badr al-Mawṣilī (d. 622/1225), for example, wrote the book Sufficing One from Memorization and Books on Issues on which there are No Reliable Hadīths (al-Mughnī ʿan al-hifẓ wa-al-kitāb fīmā lam yaṣiḥḥa shayʾ fī al-bāb).

Early mawḍūʿāt books listed hadiths along with the isnād flaws that showed they were forged, relying on the criticisms of specific narrations made by the likes of al-Bukhārī and Ibn ʿAdī. This was highly problematic, since these books implied that any hadith with that wording was forged, while there might be other, sound narrations. In the mid twelfth century the genre began shifting to openly rejecting hadiths because of their meaning. The mawdūʿāt book of al-Jawzaqānī (d. 543/1148–9), for example, states “Every hadith that contradicts the Sunnah is cast away and the person who says it is rejected as a transmitter.” This process reached a plateau with the al-Manār al-munīf fī al-ṣaḥīḥ wa-al-daʿīf (The Lofty Lighthouse for Authentic and Weak Hadiths), the mawḍūʿāt book of Ibn Qayyim al-Jawzīyah (d. 751/1350), who devoted a large section of the work to listing all the features of a hadith’s contents that demonstrated it was forged.

Of course, freely engaging in content criticism was opening a Pandora’s box. A critic might fall into exactly that trap that the early ahl al-ḥadīth claimed they were avoiding: making man’s flawed reason the arbiter of religious truth. Although later critics would maintain, as Ibn al-Jawzī states, that “any hadith that you see contradicting reason or fundamental principles [of Islam], know that it is forged,” they would also insist that one should not be too hasty in such judgments. After all, the critic might not have grasped the proper way of reconciling such contradictions. A few Sunni hadith critics in the later period, such as al-Dhahabī (d. 748/1348) and ʿAbd Allāh al-Ghumārī (d. 1993), seemed at ease openly rejecting hadiths based on their contents, sometimes even when their isnāds seemed sound. But the mainstream Sunni tradition is much better exemplified by scholars like al-Suyūṭī and Mullā ʿAlī al-Qārī. The former warned that a hadith could be rejected due to its contents only after all efforts to reconcile its meaning with the Qur’an and established Sunnah had failed. And “the door of possible interpretation is definitely wide,” added al-Qārī. Prominent scholars declared a hadith in which the Prophet ﷺ dreamt he saw God as a beardless youth to be a blatant forgery due to its anthropomorphism. Al-Qārī replied that dreams are merely symbolic, not reality. Thus, he argued, the hadith’s meaning was sound. This tension between submitting one’s reason to a transmitted text and using one’s reason to evaluate the text’s authenticity has furnished fertile ground for debate among Muslim scholars until today. 

From the time of Mālik (d. 179/795) to the late ninth century, hadith critics conceived of hadiths as falling between two poles in terms of the strength of their isnāds: ṣaḥīḥ (‘sound,’ ‘authentic’) and daʿīf/saqīm (‘weak’ or ‘unsound,’ literally ‘sick’). In terms of their level of corroboration, critics described hadiths as being ‘well-known’ (mashhūr) or ‘unacceptable, unknown’ (munkar). A hadith that was declared ṣaḥīḥ or mashhūr represented the authenticated words of the Prophet ﷺ, while weak or munkar hadiths were those not fully established as emanating from him.

It is difficult to know exactly how early hadith critics defined ṣaḥīḥ hadiths, since they were very laconic in their works. Ibn Khuzaymah defined the hadiths that he selected for his ṣaḥīḥ collection as those “that an upright (ʿadl) transmitter narrates from another upstanding transmitter continuously to [the Prophet] without any break in the isnād or any impugning of the transmitters.” Later analysts such as Ibn al-Ṣalāḥ (d. 643/1245) and Ibn Ḥajar al-ʿAsqalānī (d. 852/1449) examined the methodologies of the early masters and defined a ṣaḥīḥ hadith as one narrated by an unbroken isnād of reliable (thiqah) transmitters, namely those who combined upstandingness and accuracy, all the way back to Prophet ﷺ without any concealed flaws (ʿilal) or contradicting a more reliable source.

For hadith scholars of the eighth and ninth centuries, any hadith that did not reach the standard of ṣaḥīḥ was declared ‘weak.’ The category of ‘weak’ hadiths was thus very broad, ranging from hadiths whose isnāds suggested they were forged to those with relatively minor flaws (see Figure 1). This helps explain why ahl al-ḥadīth jurists like Ibn Ḥanbal were willing to employ hadiths they themselves described as ‘weak’ for deriving laws when no other evidence was available. The later scholar of Ibn Hanbal’s school of law, Ibn Taymiyyah (d. 728/1328), explains that weak hadiths fell into one of two categories: 1) those that did not have a ṣaḥīḥ isnād but were still reliable enough that one could use them in law, 2) hadiths that were so unreliable that they had to be set aside.

Beginning with the work of al-Bukhārī’s student Abū ʿĪsá al-Tirmidhī (d. 279/892), hadith scholars developed a new name to describe the hadiths that were not ṣaḥīḥ but still strong enough to use as proof in Islamic law: ḥasan, or ‘fair.’ Al-Tirmidhī describes a ḥasan hadith as one that “does not have in its isnād someone who is accused of lying or forgery, is not anomalous (shādhdh), and is narrated via more than one chain of transmission.” For al-Tirmidhī, a ḥasan hadith was thus a report whose isnād was not seriously flawed and enjoyed corroboration through other narrations, which mitigated the chances of a serious error creeping into the text of the report. The later jurist and hadith scholar al-Khaṭṭābī (d. 388/998) described ḥasan hadiths as those “with an established basis and whose transmitters were well-known.”

All Sunni scholars have accepted both ṣaḥīḥ and ḥasan hadiths as compelling proofs in matters of law. The subject of theology was more contested, and there was prolonged debate over whether hadiths narrated through a handful of isnāds were reliable enough to inform Islamic dogma.

Just as we do today, Muslim critics felt that certain topics required more strenuous efforts at authentication than others. From the times of early critics and ahl al-ḥadīth jurists like Ibn al-Mubārak and Ibn Ḥanbal, it was accepted that hadiths that were not reliable enough to be admitted in discussions of law could still be used for other purposes. When Ibn al-Mubārak was asked what to do with the hadiths of one weak narrator, he replied that they should not be used as proof in legal discussions. “It is still,” however, “possible to narrate from him what he has [said] on issues like good manners (adab), goodly preaching (mawʿiẓah), pious abstemiousness (zuhd), and such things.” Ibn Ḥanbal stated:

If we are told hadiths from the Messenger of God concerning what is permissible and forbidden, the sunan and laws, then we are strict with their isnāds. But if we are told hadiths from the Prophet about the virtues of certain acts (faḍāʾil al-aʿmāl), or what does not create a rule or remove one, then we are lax with the isnāds.

In addition to moralizing or exhortatory preaching, the standards for hadith authenticity also dropped for genres outside what was considered the purview of musnad hadiths, or hadiths with full isnāds originating with the Prophet ﷺ and generally addressing legal issues. These included stories about the Prophet’s campaigns and the subsequent Islamic conquests (maghāzī), reports from Companions and Successors about the meanings of Qur’anic words or the contexts in which Qur’anic verses were revealed (tafsīr), and stories foretelling the end of days (malāḥim). As Ibn Ḥanbal stated, these three genres “had no basis” (aṣl)—namely, they often consisted of statements made by Companions or Successors. In other words, they were often not Prophetic hadiths at all.

Even when such reports were attributed to the Prophet ﷺ, the critics’ standards were lax. Maghāzī, along with what emerged as the genre of ‘history’ (tārīkh), demanded less rigor because scholars did not feel that they impacted the core of the Islamic tradition: law, dogma, and ritual. Malāḥim hadiths, like hadiths dealing with good manners or urging Muslims to do good deeds, were admitted for use in teaching even if their contents were not reliable, because they encouraged Muslims to fear God.

Here we can note a remarkable feature of the way in which Sunni Muslims understood the boundaries of religion and prioritized the functions of scripture. Today we consider the stories that religious traditions tell about the apocalypse and the means by which they propagate a moral vision of the world to be essential dimensions of a faith. For Muslims in the classical period, however, they were merely tools by which scholars could purvey the true substance of Islam, which the hadith tradition was designed to preserve: law, ritual, and essential beliefs about God.

Ahl al-ḥadīth jurists like al-Shāfiʿī, his student Ibn Ḥanbal, and his student al-Bukhārī understood well that one could not simply take every hadith that one heard from the Prophet ﷺ as the law. Even if a legal hadith was authentic, the Prophet could have said it in a specific circumstance, intended it for a specific person, or changed the ruling mentioned in the hadith later on. Senior scholars were thus venerated not only for their knowledge of hadiths, but also for their ability to understand how those hadiths related to one another, fit under, added to or modified Qur’anic rulings. Early expressions of the ahl al-ḥadīth legal theory appear in the chapter of al-Bukhārī’s Ṣaḥīḥ on holding fast to the Qur’an and Sunnah, and most eminently in al-Shāfiʿī’s works the Umm and the Risālah.

Another tradition of legal theory developed parallel to that of the ahl al-ḥadīth. Ḥanafī jurists of the ninth century, many of whom subscribed to the Muʿtazilite rationalist outlook, derived this system partially from the Hellenistic tradition of philosophy prevalent in the Near East before Islam. In addition to the ahl al-ḥadīth division of hadiths into ṣaḥīḥ/ḥasan/daʿīf or mashhūr/munkar, the Ḥanafī/Muʿtazilite school of legal theory elaborated a gradated system based on the level of certainty that various forms of reports conveyed. Reports about the past, whether hadiths or simply historical accounts, that were so widespread that they could not have been forged by any one group were called mutawātir (massive parallel transmission) and yielded epistemologically certain knowledge (ʿilm yaqīn). One might not have ever actually gone to China, but the number of reports that one has heard about it convey utter certainty that the place actually exists. There was a wide range of opinions among Muʿtazilite scholars about how many transmissions of a report were required to make it mutawātir, with scholars asserting anywhere from four (the number of witnesses required in Islamic law to prove a case of adultery) to seventy (the number of people believed to have accompanied Moses up Mount Sinai to receive the Ten Commandments). This number was required at every stage of transmission. Any hadith that did not fulfill the requirements for a mutawātir hadith was known as āḥād, or a hadith of individual narrators. Unlike mutawātir hadiths, āḥād hadiths only yielded strong probability (ẓann) of what the report described.

As we have seen, Muʿtazilites had no compunction about making content criticism the centerpiece of their method of hadith evaluation. The Ḥanafī judge ʿĪsá ibn Abān (d. 221/836) thus argued that the early Muslim community rejected āḥād reports that contradicted the Qur’an or established Sunnah, or that described an event that would have been more widely reported had it really occurred. He also makes the verdict of reason the ultimate arbiter for judging the veracity of a report, not the isnād.

Although Sunnis considered Muʿtazilism to be a heresy, Muʿtazilite legal theory and its perspective on hadiths had a major impact on Sunni legal theory. A seminal figure in Sunni legal theory and theology, Abū al-Ḥasan al-Ashʿarī (d. 324/935–6), was a former Muʿtazilite who had embraced the Sunni theological worldview and then used Muʿtazilite rationalism to defend it. The major architects of what is known as the Jumhūr (Majority) school of Sunni legal theory followed in his footsteps, essentially tailoring Mu‘tazilite thought to the contours of Sunni belief. In the early 1000s, two of the most influential Shāfiʿī legal theorists, al-Qāḍī ʿAbd al-Jabbār (d. 415/1025) and his student Abū al-Ḥusayn al-Baṣrī (d. 436/1044), were actually Muʿtazilites in their conception of knowledge and theology. Their works in this field greatly informed the scholars who defined Sunni legal theory after them, such as al-Juwaynī (d. 478/1085) and his student Abū Ḥāmid al-Ghazālī (d. 505/1111).

With the work of the hadith master al-Khaṭīb al-Baghdādī (d. 463/1071), the Muʿtazilite-inspired thinking of Sunni legal theorists entered Sunni hadith criticism. Specifically, al-Khaṭīb and all the theorists of hadith criticism who followed him adopted the division of hadiths into mutawātir and āḥād along with the levels of certainty they yielded. Mutawātir hadiths yielded total certainty that the Prophet ﷺ had in fact said the report, while āḥād hadiths yielded only strong probability. This was, however, strong enough for them to be used in deriving law.

Sunni legal theorists introduced a middle tier between āḥād and mutawātir dubbed ‘widespread’ (mashhūr or mustafīḍ). These hadiths were reports that started out as āḥād, being transmitted by only a few people in the first few generations, before spreading out and becoming mutawātir. But because these hadiths had been accepted as reliable by the community of scholars, they were known to be authentic. This was based on the Sunni belief, phrased in the Prophet’s words, that “God will not let my community agree on an error.” Hadith criticism also absorbed the principles of content criticism described by Ibn Abān.

The result of this merging was a composite tradition that joined two perspectives on hadith criticism that were originally in opposition, if not antithetical, to one another. Since the eleventh century, Sunni hadith criticism has therefore produced many internal contradictions. The most prominent display of this has been theories of hadith criticism that do not correspond to the work of hadith critics. We have already seen how the Sunni legal theorist’s definition of upstanding character (ʿadālah) did not apply at all to the criteria that early hadith critics like al-Bukhārī used to determine the reliability of a narrator. In terms of content criticism, al-Khaṭīb al-Baghdādī affirms the principles derived from Ibn Abān. Not once, however, in the course of his criticism of the thousands of hadiths in his vast History of Baghdad does al-Khaṭīb openly reject a hadith because its contents were unacceptable! As mentioned earlier, it was not until the mawḍūʿāt work of al-Jawzaqānī (d. 543/1148-9) and those who followed him that Sunni hadith critics actually overtly applied rules of content criticism in the course of their hadith evaluations. Even then their use of content criticism was fraught with tension. Essentially every Sunni hadith scholar since al-Khaṭīb has upheld Ibn Abān’s rules of content criticism. But few have applied them.

The categories of mutawātir and āḥād were similarly unsuitable for the hadith tradition, for essentially all hadiths were āḥād. As Ibn al-Ṣalāḥ (d. 643/1245), the most famous scholar of hadith criticism in the later period, explained, at most one hadith (“Whoever lies about me intentionally, let him prepare for himself a seat in Hellfire”) would meet the requirements for mutawātir. No hadiths could actually be described as being narrated by a large number of narrators at every stage of their transmission. In fact, when Muʿtazilites had insisted that hadiths be transmitted by a mere two people at every stage, the Sunni Ibn Ḥibbān accused them of trying to destroy the Sunnah of the Prophet ﷺ in its entirety.

The absorption of Muʿtazilite legal theory into the Sunni hadith tradition in the 1000s is indicative of the major changes that occurred in the later period of hadith criticism. From the eleventh century onward, hadith criticism would be characterized by an increasing distance from the methods of early critics. Especially with the solidification of the Late Sunni Tradition (the four madhhabs, dominance of Ashʿarī/Māturīdī theology, and Sufism) in the 1300s, we can see a tendency towards authenticating more and more hadiths that had previously been considered outside the pale of usage. Partially explained by the broader perspective enjoyed by later critics and partially justified by manipulations of the methods of hadith critics, hadith criticism became an increasingly ‘Big Tent’ of inclusivity.

We note the beginning of the critical laxity of the later period in the Mustadrak collection of al-Ḥākim al-Naysābūrī (d. 405/1014), in which the author claimed he had collected thousands of hadiths that met the authenticity requirements of al-Bukhārī and Muslim. In reality, however, al-Ḥākim’s methods of authentication fell far short of those of his two predecessors. He declared a hadith authentic if its isnād consisted of transmitters used in the Ṣaḥīḥayn or transmitters similar to them. The later analyst Jamāl al-Dīn al-Zaylaʿī (d. 762/1361), however, uncovered the weakness at the heart of al-Hākim’s strategy: he had relied on the same transmitters as al-Bukhārī and Muslim, but he did not examine the hadiths for corroboration or ensure contiguous transmission. According to al-Dhahabī, only half of the Mustadrak’s contents were actually authentic. The other half were of dubious reliability.

Neglecting the need for corroboration has been a hallmark of later hadith criticism. Whereas a critic like al-Bukhārī would accept a hadith narrated by only one chain of transmission as long as it consisted of master scholars like al-Zuhrī and Mālik, later critics often authenticated hadiths based on only one chain regardless of the inferior standing of some transmitters. Ibn Abī Ḥātim, Ibn ʿAdī, and other early critics had declared the hadith saying that “The most truthful speech is that said after sneezing” was weak or forged. In the thirteenth century, however, al-Nawawī (d. 676/1277) argued for its reliability based on a solitary narration from the Musnad of Abū Yaʿlá al-Mawṣilī (d. 307/919) even though one of its transmitters had been severely impugned.

Later critics did have one tangible advantage over earlier critics. A later scholar like Ibn Ḥajar or al-Suyūṭī had access to works that consolidated and synthesized the vast and diverse expanse of the hadith corpus as well as collections that might not have been within reach of an early critic. Where early critics like al-Bukhārī or al-Tirmidhī had access to only some narrations of a Prophetic tradition when they declared it weak, in the 1400s Ibn Ḥajar could take into consideration additional narrations that might raise that hadith to ḥasan or ṣaḥīḥ status. Ibn al-Ṣalāḥ used the term ‘ḥasan due to other narrations’ (ḥasan li-ghayrihi) and ‘authentic due to other narrations’ (ṣaḥīḥ li-ghayrihi) to describe this procedure. The twentieth-century Moroccan hadith scholar Aḥmad al-Ghumārī (d. 1960) exemplified later scholars’ access to material out of the reach of an early critic by writing a book entitled Not So (Laysa kadhālik), in which he used new evidence to rebut a series of statements that early critics like Ibn Ḥanbal made about transmitters and hadiths.

Of course, while later critics could authenticate a hadith that had previously been considered unreliable, the opposite was theoretically very difficult. When al-Bukhārī judged a hadith to be ṣaḥīḥ, his decision was based on information about the hadith that may have been subsequently lost to history. As Ibn Taymiyyah explains, “whatever hadiths reached [early scholars] and that they deemed authentic may only have come down to us through unknown transmitters, broken isnāds or not at all.” How, then, could a later scholar question the authentication of an earlier master?

Not all the previously inaccessible evidence to which later hadith critics had access, however, was reliable according to the hadith critical method. Scholars of the Late Sunni Tradition made large numbers of hadiths admissible in religious discourse by exploiting the tremendous range of questionable hadiths found in the late musnad collections of the tenth to twelfth centuries as well as the principle that weak hadiths were acceptable as proof on non-legal issues. Basing their argument on the above-mentioned stance of early masters like Ibn Ḥanbal, leading late Sunni scholars like al-Nawawī and al-Suyūṭī all agreed that as long as a hadith was not forged it could be used in any discussion not concerning theology or the prohibition and permissibility of an act. In order to raise a hadith to the level of admissibility in such cases, all a scholar had to do was prove that it was not forged—proving that it was merely ‘weak’ sufficed. This was the course of action that al-Suyūṭī admitted to taking when he presented hadiths supporting his argument that the Prophet’s parents were destined for Heaven even though they had never known Islam during their lives.

In order to rehabilitate a hadith that critics had earlier declared a forgery, one had to provide evidence that it had some ‘basis’ (aṣl) in the early Islamic tradition. For example, even though there might not be enough evidence to trace a hadith authentically to the Prophet ﷺ, a weak hadith might be the result of a Companion’s statement or an early legal ruling that had accidentally been attributed to Muhammad. It was still a legitimate indicator of proper Islamic values.

The most frequently cited sources for finding such an ‘aṣl’ for a hadith were the Musnad al-Shihāb of al-Quḍāʿī (d. 454/1062) and the Musnad al-Firdaws of al-Daylamī (d. 558/1163), both late works infamous for the unreliability of their contents. When Mullā ʿAlī Qārī argued for accepting the hadith “Wiping one’s neck [during ablutions] is protection against fetters [on the Day of Judgment]” (masḥ al-raqabah amān min al-ghill), which al-Nawawī had said was forged and which other critics had declared a Companion statement, he announced that a Prophetic version was found in the Musnad al-Firdaws and thus that the hadith was weak, not forged. “And weak hadiths,” he added, “are acted on by consensus for establishing the virtues of actions.”

When attempting to raise a weak hadith to the status of ‘ḥasan due to other narrations,’ the evidence to which later critics often resorted were the narrations that earlier critics like Ibn ʿAdī or al-Bukhārī had listed in their weak transmitter collections to show a certain person’s flawed hadiths. Although the early masters Ibn Maʿīn, al-Bukhārī, Abū Zurʿah al-Rāzī , al-Tirmidhī, Ibn ʿAdī, al-Dāraquṭnī, and al-Khaṭīb al-Baghdādī all declared that various versions of the hadith “I am the city of knowledge and ʿAlī is its gate” were baseless, later critics such as al-ʿAlāʾī (d. 761/1359), Ibn Ḥajar, and al-Suyūṭī all agreed that, when taken together, these narrations made the hadith ḥasan.

The final means by which hadiths achieved exaggerated authority in the Late Sunni Tradition was the exploitation of the concept of mutawātir reports. It was accepted by consensus among Sunni scholars that if a report had reached the level of mutawātir it was utterly certain that the Prophet ﷺ had said it. Although scholars like Ibn al-Salāh had declared that no such hadith existed in actuality, al-Suyūṭī composed a collection titled al-Azhār al-mutanāthirah fī al-aḥādīth al-mutawātirah (The Scattered Flowers of Massively Transmitted Hadiths) in which he included 111 hadiths he declared mutawātir because ten or more Companions had narrated them from the Prophet. But a mutawātir hadith had to have such a number of isnāds at every level of transmission, and not all the chains of transmission that al-Suyūṭī used as evidence were reliable to begin with. Because the concept of mutawātir was so ambiguous, later critics could abuse the label to argue for the undeniable authenticity of a hadith they were citing. 

How do we explain seemingly deceptive tactics like the exploitation of weak hadiths by late Sunni scholars? Were they not pious defenders of the hadith tradition, whose whole purpose was “to ward off lies from the Prophet of God”? Although we might note that the Late Sunni Tradition was very permissive with hadiths, scholars like al-Suyūṭī felt they were on firm ground. In the case of the Prophet’s parents going to heaven, after all, al-Suyūṭī did not just have hadiths in mind when attempting to prove his case. He had the whole heritage of Islamic thought at his disposal, such as Qur’anic verses saying that “No bearer of burdens will bear the burdens of another” and theological principles such as the Sunni tenet that people born in a community before its prophet arrives will not be held accountable for ignorance of God’s religion. In the early period of Islam, if the Muslim community’s practice agreed with a hadith, then that hadith was considered reliable even if its isnād was poor. This was the same approach taken by the Late Sunni Tradition; if centuries of Muslim scholars had agreed that the meaning of a hadith was accurate, then ascribing it to the Prophet ﷺ was acceptable as well. And, as Ibn al-Qayyim said, such a hadith, “even if it has not been established as reliable, the fact that it has been acted on in all regions and eras with no rejection is sufficient for us to act on it.” Of course, this assumes that those centuries of Muslim scholars were right.

Islamic civilization has accorded great credence to dreams or inspired visions in which Muslims encounter the Prophet ﷺ. This is based on two ṣaḥīḥ hadiths: “Nothing of prophethood will remain after me except righteous nightly dreams,” and “Whoever has seen me in a dream has seen me while awake, for indeed Satan does not assume my form.” Seeing the Prophet in a dream is thus a reliable experience with probative value. Muslim jurists and legal theorists, however, have agreed unanimously that, while a vision of the Prophet may reveal truths to someone concerning personal matters, it cannot have any effect on law or formal relationships. It cannot excuse you from work or school.

In the first few centuries of the hadith tradition, dreams and visions therefore played a colorful but ultimately superficial role in hadith authentication. Al-Ṭabarānī had a dream in which he asked the Prophet ﷺ about the status of the hadith, “The believers in their mercy towards one another are like a man part of whose body is in pain—the rest of his body feels the pain.” The Prophet replied “Ṣaḥīḥ, ṣaḥīḥ, ṣaḥīḥ!” This hadith, however, had already been authenticated by al-Bukhārī and Muslim, so al-Ṭabarānī’s inspired vision effected no change in its standing.

The Late Sunni Tradition was characterized by a more prominent and novel method of facilitating hadith authentication: illuminating inspiration, or ‘kashf’ (literally, ‘unveiling’). This method was developed by the influential and highly controversial Sufi systematizer Ibn ʿArabī (d. 638/1240). For Ibn ʿArabī, receiving revelatory inspiration (kashf) from contact with God’s ultimate truth as reflected in the ‘Muhammadan reality,’ was one of the three means by which a human could acquire sound religious knowledge. Unlike the other two methods, rational investigation and prophetic revelation, however, kashf allowed the saint on whom God bestowed this power to place the knowledge attained by these other methods in their proper place.

As Ibn ʿArabī explained, weak hadiths are not valid proofs because they lack a reliable isnād. But some of these reports might in fact be real sayings of the Prophet ﷺ that have gone unrecognized because of poor transmitters. If one could find a reliable isnād for such a hadith, then it could be acted on. A saint who receives direct, unveiling knowledge from God is like a Companion hearing this hadith from the Prophet, except that he hears it from the eternal Prophetic light. His inspiration can inform him that the Prophet actually said that hadith since, like a Companion, the saint is actually in the Prophet’s presence.

Like other legal theorists, however, Ibn ʿArabī acknowledges that a hadith authenticated by kashf cannot be used in legal arguments. But he does contend that kashf can reveal to a saint that a certain hadith that had been authenticated by traditional hadith criticism was in fact forged.

Hadith critics of the Late Sunni Tradition adopted Ibn ʿArabī’s belief that inspiration provided proof that a hadith was authentic provided that it did not affect law, although the technique has found little use outside the work of a few scholars like the North African Sufi ʿAbd al-ʿAzīz al-Dabbāgh (d. 1719) (who claimed to have heard hadiths from the Prophet ﷺ via the sole intermediary of Khaḍir). Almost no critics have accepted that kashf could overrule a ṣaḥīḥ ruling arrived at by the traditional methods of hadith criticism. Some scholars have squarely rejected any allowance for kashf in hadith—the Egyptian Mālikī scholar Muhammad ʿIllaysh (d. 1882) stated, “There is no room for such laxity in the religion of God, and sainthood and miracles have no role in this issue [of hadith authentication]. Rather, recourse is to the hadith masters knowledgeable about this matter.”

The same general rule applies to hadiths narrated via jinn, which begin appearing in books in the 900s CE. The issue of authenticating such narrations does not seem to have come up in the pre-modern period, probably because hadiths from jinn are rare and concern matters unrelated to law or belief. The Ottoman hadith master al-Kawtharī (d. 1952) and the Moroccan Sufi and traditionalist hadith scholar Aḥmad al-Ghumārī (d. 1960), however, both rejected the reliability of any narration via jinn. This was for the same reason that Ibn Abī Zayd (d. 386/996) prohibited charging money for jinn exorcisms: one could not verify whether someone had actually encountered a jinn or even if it existed.

It was indeed possible to encounter the Prophet ﷺ in dreams, and the Qur’an leaves no doubt that jinn exist. But neither of these means could convey hadiths reliably because neither dreams nor an encounter with jinn had a transitive property of proof; they could not be verified by others. Narrating hadiths via superannuated (i.e., extremely long-lived, Arabic: muʿammarūn) transmitters was a different matter. Since the Qur’an describes Noah living at least 950 years (29:13-4) and because Sunni doctrine holds that God can break the normal functioning of nature and society (ʿādah), as in the case of the miracles of prophets and saints, a hadith transmitter could live a miraculously long time. 

Muslim hadith scholars, however, often rejected allegedly superannuated transmitters for reasons other than physical impossibility. Several narrations of Ṣaḥīḥ al-Bukhārī (i.e., the transmission of the Ṣaḥīḥ from al-Bukhārī to later generations) and other major works relied on superannuated narrators. These miraculous transmissions of the books were in no way important for preserving them; there were plenty of reliable, unremarkable isnāds to the Ṣaḥīḥayn and to the Musnad of Ibn Ḥanbal, and the books were too well known for any danger of alteration. Transmission via muʿammarūn was just an occasion for Muslim scholars to indulge the spirit of collectors and to feel closer to the Prophet’s blessing (barakah). As hadith scholars like the Moroccan ʿAbd al-Ḥayy al-Kattānī (d. 1963) observed, however, the superannuated chain for Ṣaḥīḥ al-Bukhārī and other books “had problems, each one bigger than its sibling.” There were too many inconsistencies and errors in who narrated from whom when, and in particular about who and how old the famous—perhaps apocryphal—Bābā Yūsuf al-Harawī was (a.k.a, ‘Son of Three-Hundred Years’). Al-Khaṭīb al-Baghdādī mentions that a figure named Ibn al-Dunyā (d. 327/937) arrived in Baghdad around 910 CE, claiming to have found the fountain of youth centuries earlier and to have heard  hadiths directly from the caliph ʿAlī. But “the scholars of transmission have not substantiated his claim and do not accept his hadiths as proof,” says al-Khaṭīb. Baghdad hadith scholars just did not trust him. 

Some transmitters were not just superannuated. They also claimed to have met the Prophet ﷺ, which would raise them to the level of Companion in Sunni Islam and meant that it was not possible for them to intentionally lie about the Prophet. The most famous case was Ratan al-Hindī (d. circa 632/1235), who appeared in India in the early 1200s claiming to be a Companion. This irked al-Dhahabī greatly, and he penned a small treatise entitled Breaking the Idol of Ratan (Kasr wathan Ratan). Ratan was an egregious liar, al-Dhahabī argued, since no one had heard of him for the six centuries prior to his ‘claim.’ This violated the uṣūl principle that a report could not be true if it described an event that, if it had actually happened, would have been more widely reported. Moreover, towards the end of his life, the Prophet had said in hadith agreed upon as authentic that none of his Companions would be alive a hundred years from then. 

Some Muslims wondered if seeing the Prophet ﷺ in a dream made them a Companion, since the Prophet had said, “Whoever sees me in a dream has seen something true.” But Ibn Ḥajar explained that this vision involved ‘spiritual matters,’ not the rulings of earthly life.

By the 1200s the collection of hadiths had come to an end, and hadith scholars devoted themselves to consolidation, commentary, and criticism. With the hadith canon firmly established, hadith critics turned their attention away from hadith collections and toward the manner in which other areas of Islamic scholarship used hadiths. In books of takhrīj, a rash of which appeared during the 1300s and 1400s, a hadith scholar took a book from another genre and discussed the status of the hadiths it contained. Since few books outside hadith collections featured isnāds when they quoted hadiths, takhrīj books first provided all the hadith collections that provided chains of transmission for a hadith and then sometimes discussed its reliability.

The earliest known takhrīj book was the work that ʿAbd al-ʿAẓīm al-Mundhirī (d. 656/1258) devoted to the Muhadhdhab, a major work of Shāfi‘ī law written by Abū Isḥāq al-Shīrāzī (d. 476/1083). Many takhrīj books devoted to works of Islamic law followed. The Ḥanafī al-Zaylaʿī produced his famous Naṣb al-rāyah (Erecting the Standard), a takhrīj of the hadiths in the Hidāyah, a formative Hanafī law book by al-Marghīnānī (d. 593/1196–7). Ibn al-Mulaqqin (d. 804/1401) and Ibn Ḥajar wrote their Badr al-munīr and Talkhīs al-ḥabīr respectively, both devoted to the hadiths included in the major Shāfiʿī legal text of al-Rāfiʿī. Several takhrīj books dealt with the hadiths cited in prominent books of legal theory, such as Ibn Kathīr’s Tuḥfat al-ṭālib, which addressed the contents of Ibn al-Ḥājib’s abridged treatise on legal theory. Ibn Ḥajar also devoted a takhrīj work to the Kashshāf, the famous Qur’anic commentary by al-Zamakhsharī (d. 538/1144). Renowned Sufi texts also attracted takhrījs. Ibn Ḥajar’s teacher Zayn al-Dīn al-ʿIrāqī (d. 806/1404) wrote a very critical takhrīj of the hadiths that al-Ghazālī had used as proof in his famous but controversial opus, the Ihyāʾ ʿulūm al-dīn (Revival of the Religious Sciences). Ibn Hajar’s student, Shams al-Dīn al-Sakhāwī (d. 902/1497), wrote a takhrīj of al-Sulamī’s popular Forty Hadith collection on Sufism.

Later hadith scholars also directed their hadith criticism towards Muslim society as a whole. A whole genre of books emerged that took takhrīj ‘to the streets,’ examining hadiths that were widespread in Muslim society. Ibn al-Jawzī, Ibn Taymiyyah, and al-ʿIrāqī each wrote a book analyzing and criticizing the often baseless hadiths recited by popular storytellers (quṣṣās). Books of ‘mushtahir,’ or ‘well-known,’ hadiths examined hadiths popular in everyday Muslim life in order to determine if they had any basis in the Prophet’s speech and judged their reliability. Badr al-Dīn al-Zarkashī (d. 794/1392) wrote the first known book in this genre. Al-Sakhāwī’s al-Maqāṣid al-ḥasanah and Ismāʿīl al-ʿAjlūnī’s (d. 1748-9) Kashf al-khafāʾ are the most famous books on mushtahir hadiths.