Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that among the polytheists, some had committed the sin of murder, and had done so excessively. Similarly, they used to commit adultery in abundance. Then they came to the Prophet Muhammad (peace and blessings be upon him) and said, "What you say and what you invite us to (i.e., Islam) is certainly a good thing, but tell us, will the sins we have committed so far be forgiven if we accept Islam or not?" Upon this, this verse was revealed: "And those who do not call upon any other god besides Allah, nor kill a soul which Allah has forbidden except by right, nor commit adultery. And whoever does this shall meet a severe penalty." (__QUR_25:68__) And this verse was revealed: "Say, 'O My servants who have transgressed against themselves, do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, He is the Most Forgiving, Most Merciful.'" (__QUR_39:53__)