Is Allah really more merciful with us than even our own mothers? How can that be possible when He created Hellfire and will cast some people into it?
The study Modern Pathways to Doubt in Islam, published by the Yaqeen Institute, determined that many young Muslims find it difficult to reconcile the idea of a Merciful God with the existence of hellfire. Similarly, the claim of the “New Atheists” that the very concept of tortuous damnation found within Islam and Christianity grates against our sense of justice. As a result, many Muslims today need to understand this concept in order to restore their faith and conviction in the Almighty. In this particular paper, we will not delve into the impossibility of sizing up an infinite and unseen God through the limited lens of finite human perception, nor the many writings of Muslim and Christian theologians across the centuries about reconciling God’s mercy with His punishment. This case study will focus on one famous tradition of the Prophet Muhammad ﷺ regarding God's mercy and the hellfire and will refute the claim that this tradition is counterintuitive. 
‘Umar b. al-Khaṭṭāb (may Allah be pleased with him) narrates that a captive woman was once [frantically] searching until she suddenly found a small boy among the captives. She pulled him to her stomach and breastfed him, at which point the Messenger of Allah ﷺ said to us, “Do you think this woman would throw her child into a fire?” We said, “No, O Messenger of Allah, not while she is capable of not throwing him.” The Messenger of Allah ﷺ said, “Allah is certainly more merciful with His servants than this woman is with her child.”[1]
Allah (the Majestic) describes Himself repeatedly in the Qur'an as Arḥam ar-Rāḥimeen (literally: the most merciful of those who show mercy),[2] and says that His mercy encompasses all things.[3] His Prophet ﷺ described Him as more merciful with His servants than a mother is with her child, and more merciful with His servant than the servant is with himself. There is no clearer, more recurring, fact in the Qur'an or Sunnah, after that of Allah being unique in His Oneness, than that He possesses unimaginable mercy and compassion. How then can this be reconciled with the fact that God would punish some people with Hellfire?

Allah must be more merciful than all since He is the One who endowed His creation with the aptitude for mercy in the first place

A mother’s mercy is but a fraction of Allah’s universal mercy which every human being enjoys in this life

Allah has reserved an even greater mercy for the believers in the afterlife

Though the mercy of Allah is without limits, Allah is not limited by His mercy

Allah's sending His messengers and scriptures to mankind and inspiring people to recognize and embody guidance is the greatest mercy of all

Punishment in the Hellfire contains multiple layers of mercy