Al-Matalib al-'Aliyah 3256 — Repentance and seeking forgiveness

It is narrated from Sayyiduna Mu'awiyah bin Abi Sufyan (may Allah be pleased with him) that I heard the Messenger of Allah (peace and blessings be upon him) say: "Among those who passed before you there was a man who met a scholar or a worshipper and said to him that he had killed ninety-nine people, purely out of injustice and wrongdoing: do you find any way of repentance for me? He said: No. So that man killed him too. Then he met another man and said that he had killed a hundred souls unjustly: do you find any scope of repentance for me? He replied: If I were to tell you that Allah, the Blessed and Exalted, does not accept the repentance of one who repents, I would certainly have lied. Here there is a place of worship in which some people are occupied in the worship of Allah; go to them and worship Allah, the Mighty and Majestic, together with them; perhaps Allah Almighty will accept your repentance. So he set out towards them, but death overtook him before he reached there. Thereupon the angels of punishment and the angels of mercy disputed. Then Allah Almighty sent an angel (who commanded): Measure the distance between the two places; whichever settlement he is found nearer to, he will be counted among its people. When they measured the distance, they found him nearer to the place of worship of the repentant by the length of a fingertip. So Allah, the Mighty and Majestic, forgave him."
Takhrij: The chain of this hadith is hasan (good), and the basis of this incident is also found in Sahih al-Bukhari and Sahih Muslim.