Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates: Once the Prophet Muhammad (peace and blessings be upon him) led a prayer. The narrator of this narration, Ibrahim, says: I do not know whether any addition or omission was mentioned regarding this prayer of the Prophet (peace be upon him). (Sayyiduna Abdullah, may Allah be pleased with him, narrates:) When the Prophet (peace be upon him) finished the prayer with salam, it was said to him: O Messenger of Allah! Has any new command regarding the prayer been revealed? The Prophet (peace be upon him) said: "No, why, what happened?" The people said: You performed the prayer in such and such a manner. So the Prophet (peace be upon him) stretched out his legs, turned his face towards the qiblah, performed two prostrations of forgetfulness (sajda sahw), and then finished with salam. When he finished with salam, he turned towards us and said: "If any new command regarding the prayer had been revealed, I would have informed you. I am also a human being; I forget just as you forget. So if I forget something, remind me. And when a person is in doubt about his prayer, he should try to determine what is correct, then complete the prayer accordingly, then finish with salam, and after that perform two prostrations of forgetfulness."