Hazrat Abu Burdah narrates that I heard Hazrat Abdullah bin Umar (may Allah be pleased with them both) supplicating as follows: "My Lord, whatever You have bestowed upon me, I will never be a helper of the criminals." Then, when he performed the prayer, he said: "I have not performed any prayer except that I hope it is an expiation for the sins that are to come." The meaning is that he said these words while in the state of bowing (ruku).