Sahih Muslim Book 35, Hadith Number 6557.
Chapter : Refuge from the evil of what one has done, and what one has not done.
Farwa’ b. Naufal Ashja’i reported: I asked: ‘Aisha, in what words did Allah’s Messenger (may peace be upon him) supplicate Allah? She said that he used to utter: “I seek refuge in Thee from the evil of what I did and from the evil of what I did not.”