Sahih Muslim Book 35, Hadith Number 6558.
Chapter : Refuge from the evil of what one has done, and what one has not done.
Farwa’ b. Naufal reported: I asked ‘Aisha about the supplication that Allah’s Messenger (may peace be upon him) made. She said that he used to say: “O Allah, I seek refuge in Thee from the evil of what I have done and from the evil of what I have not done.”