When does the changing of a penitent's evil deeds into good deeds occur: Is it at the time of reckoning, or after entering Hellfire? And does this changing include every sin, no matter how grave, such as apostasy and others?

The exegetes (ahl al-ta'wil) differed regarding the superiority of replacing evil deeds with good deeds. Some of them said that it is in this world, by the repentant person being guided to do righteous deeds instead of evil ones, and this is what Al-Tabari favored. Others said that it is in the Hereafter, whereby evil deeds are transformed into good deeds on the Day of Resurrection, and this transformation may occur before entering Hellfire or after it. Al-Tabari, Muslim, and Ahmad narrated from Abu Dharr a hadith that a man will be brought forth on the Day of Resurrection, and his evil deeds will be replaced with good deeds. Apostasy (riddah) is included in this transformation if the Muslim repents from it, based on the Almighty's saying: "Except for those who repent, believe and do righteous work. For them Allah will change their evil deeds into good ones. And Allah is ever Forgiving, Most Merciful."