Ibn Yasaf said:
I asked 'Aishah, what was the supplication that the Prophet [SAW] said the most? She said: 'The supplication that he said the most was: Allahumma, inni a'udhu bika min sharri ma 'amiltu wa min sharri ma lam a'mal ba'd (O Allah, I seek refuge with You from the evil of what I have done, and from the evil of what I have not done yet.)'