For more on this topic, see Justice in Islam
To act justly or equitably, to be fair in judgment, to be impartial in speech, or witness; to straighten someone to a state of moral uprightness, or from disbelief to faith, to offer a compensation in place of punishment for a sin, to deviate or turn away from the truth, or to set up something as equal to something else, which can have a positive connotation approximating the first of these, or a negative one referring to the sin of shirk, worshipping anything else alongside God.
Justice [al-ʿadl] is a term associated with equality [musāwāh]. It has various meanings, depending on the context. In the context of potential, it is an innate human desire for equality. In the context of action, it means dealing fairly with others. And in the context of the Divine, it describes the complete orderliness of God’s actions. In the pursuit of justice, man tries to be virtuous, but can only be perfectly virtuous if his outer actions stem from an inner noble disposition and character. Outwardly just actions do not necessarily make one a just human being. If the intention of the just action is for the sake of show, a worldly benefit, or fear of a Sultan’s punishment, it cannot be truly just.
God describes justice in terms of al-mīzān [the scale/the balance], because weighing is one of its obvious concrete actions. The Prophet Muhammad (ṣ) said, “The heavens and the earth have been established through justice.” That is to say, if the existence of the world and its principles were either more or less than what is required, the world would not be in perfect order. [Ironically], unjust people expect justice to be done: even thieves expect it from one another. If they agree on certain conditions, and some of them violate those conditions, [they are so incensed by the injustice] their relationships are thrown into chaos and disorder. Thus, each soul naturally feels happy when seeing or hearing justice, and feels unhappy to see or hear the opposite. That is why even the unjust admire just actions when they see or hear them. It is said a just person is confident of being cleared by God on the Day of Judgment. Since man has an innate sense of justice, he is grieved by the abnormalities and disorders of the world. He is sad to see someone with physical deformities like a limp or a squint. To achieve equality and symmetry, God placed single features [like the nose] in the middle, and other organs [like ears] in pairs, one on each side of the body. Imitating God’s design, painters and sculptors ensure that paintings and carvings are symmetrical and harmonious and that they are not distorted.
Justice is natural (fiṭrī) in the sense that justice as a whole precedes man and the state in time from the beginning of creation. Justice is natural because it is an integral part of the Divine principle or law that regulates the uniformity and rationality that is apparent in the whole of nature. Natural justice pertains to the nature (fiṭrah) of man as an individual.
Between him and his Creator, through living in the knowledge of His Oneness and in accordance with His Laws.
Between the faculties of the soul, so that desire submits to reason. It is said: the just man is he who is just to his intellect, not his desire.
Between him and his forefathers, following their good advice and praying for them.
In his conduct towards others, honoring their rights, and being fair to them in selling and buying and in contracts and leases.
Dispensing justice through sound judgment. This applies to governors and their agents.
First, injustice to the Almighty Lord; second, injustice to the faculties of the soul; third, injustice to the ancestors; fourth, injustice to those who deal with him from among the living; and fifth, injustice to the common people.
The most unjust person is the one who wrongs his own soul, his own relatives, and then the rest of mankind. The most just among people is one who is just to all people, his relatives and then with his soul. That is to say, the unjust person cannot be unjust to others unless he transgresses himself first.
He who cannot rule over his own soul is not suitable to rule over others. For this reason, God Most High rebukes unworthy men who wish to rule over other people, commanding good and prohibiting evil without having reformed themselves. He declares: “Do you command others to be righteous and forget yourself while you recite the Book?”
Distributive justice: Islamic economic justice
O mankind, surely We have created you from a male and a female and made you tribes and nations that you might know one another. Surely the noblest of you in the sight of God is the one who is the most pious among you (Q. 49:13).
God has prohibited hoarding the dirham and not putting it into active use in economic affairs. … Hoarding gold and silver is like locking away rulers, preventing them from managing people’s livelihood. The Prophet (ṣ) said, “He who drinks from a silver jug actually drinks the fire of hell.” Jugs and plates made of gold and silver reduce the amount of money in circulation and so stifle trade.
Rectificatory justice: Crime and punishment
The juxtaposition of iḥsān (benevolence) next to ʿadl tends to open up the scope of justice to considerations of equity and fairness. Whereas ʿadl is primarily regulated by law, the scope of iḥsān is not restrained by conformity to formal rules. Iḥsān can consist of forgiveness and returning good for evil, or doing a good turn and being generous to those who may have neither claimed nor demanded justice. The reference to financial help in the text evidently accentuates the material dimensions of both ʿadl and iḥsān.’
So pardon [their wrongs towards you] with a most graceful pardon [without grudge] (Q. 15:85);
Those who curb their anger and those who pardon their fellow men: God loves those who do good (Q. 3:134);
Yet, pardon them and forgive: God surely loves those who do good to others (Q. 5:13);
But he who pardons and makes peace, his reward is with God (Q. 42:40).