It is narrated from Hazrat Amr bin Aas (may Allah be pleased with him): When Allah Almighty created the truth of Islam in my heart, I presented myself before the Holy Prophet (peace and blessings be upon him) to pledge allegiance. The Prophet (peace and blessings be upon him) extended his blessed hand towards me. I said, "O Messenger of Allah (peace and blessings be upon him), I will not pledge allegiance to you until you forgive my past mistakes." The Prophet (peace and blessings be upon him) said, "O Amr! Do you not know that migration wipes out all the sins that came before it? O Amr! Do you not know that Islam wipes out all the sins that came before it!"