Sahih Muslim Book 35, Hadith Number 6560.
Chapter : Refuge from the evil of what one has done, and what one has not done.
Farwa’ b. Naufal reported on the authority of ‘Aisha that Allah’s Messenger (may peace be upon him) used to supplicate (in these words): “O Allah, I seek refuge in Thee from the evil of what I did and from the evil of what I did not.”