Surah Al-An'aam (6) — Ayah 54

54. And when those who believe in Our verses come to you, say to them: "Peace be upon you. Your Lord has made mercy obligatory upon Himself [57]. Whoever among you does evil in ignorance, then repents afterwards and reforms, then surely He is Most Forgiving, Most Merciful."

[57] Among the Muslims, there were some people who had committed many major sins during the time of ignorance. Although they had now greatly reformed themselves and their lives had changed, the opponents of Islam would not refrain from taunting them about their past deeds and faults. In this context, it is being said to youﷺ that give comfort to the believers and say that your Lord is Most Forgiving, Most Merciful. Whoever accepts Islam or repents and reforms himself, then Allah will certainly not hold him accountable for his past sins. As Sayyiduna Abu Sa‘id Khudri (may Allah be pleased with him) says that I heard the Prophetﷺ say: "When a person accepts Islam and does so properly, all his previous evils are removed, and after that, the reckoning will be such that for every good deed, ten to seven hundred good deeds will be written, and for every evil deed, only one evil will be written—unless Allah forgives even that." [بخاري۔ كتاب الايمان۔ باب حسن اسلام المرء] Therefore, youﷺ should assure such people that there is peace for you from Allah. Allah's mercy is vast. He will surely forgive your evils committed before accepting Islam. Then, even after that, if someone, by mistake or out of ignorance, commits a sin and then repents before Allah, then Allah is certainly Most Forgiving, Most Merciful to His servants.

[58] 1. Sayyiduna Abu Hurairah (may Allah be pleased with him) says that the Prophetﷺ said: "Allah wrote a book before creating the creation (in which it was written): My mercy has overtaken My wrath. And this is written with Him on the Throne." [بخاري كتاب التوحيد۔ باب قول الله تعالىٰ :__QUR_0__ ]

2.
The Condition of the Killer of Ninety-Nine Men:

Sayyiduna Abu Sa‘id Khudri (may Allah be pleased with him) narrates that the Prophetﷺ said: Among the Children of Israel, there was a man who had unjustly killed ninety-nine people. Then he set out to ask about his own case. He went to a monk and asked him, "Is there any room for repentance for me?" He said, "No," so he killed the monk as well (completing one hundred). Then he kept asking people the same question. Someone told him: Go to such-and-such a town (for repentance). On the way, death overtook him. He turned his chest towards the town. Now the angels of mercy and the angels of punishment began to dispute with each other. Allah commanded the town he was heading to, "Come closer," and the town he was leaving, "Go farther away," and said to the angels, "Measure the distance." So the town he was heading to was found to be a hand-span closer, so he was forgiven. [بخاري۔ كتاب الانبياء۔ باب ماذكر عن بني اسرائيل]

3. Sayyiduna Abu Sa‘id Khudri (may Allah be pleased with him) narrates from the Messenger of Allahﷺ that he mentioned a man from among the earlier people. Allah had given him wealth and children. When he was about to die, he asked his sons: "What kind of father was I to you?" They said: "You were a good father." The father said: "Look! I have not stored up any good deeds with Allah, and if I reach Allah, He will surely punish me. Therefore, do this: when I die, burn my body, and when I become coal, crush me finely and scatter my ashes in a strong wind." He made his children swear to do this. So after his death, his children did as he had asked. Allah said "Be!" and that man stood before Allah. Allah asked: "My servant! What made you do what you did?" He said: "Only fear of You made me do it." So Allah rewarded him for his fear by having mercy on him (forgiving him). [بخاري۔ كتاب الرقاق۔ باب الخوف من الله]