Hudbah ibn Khalid narrated to us: Hammam narrated to us, from Qatadah, from al-Hasan, and from Zurarah ibn Awfa, that al-Mughirah ibn Shu'bah said: The Messenger of Allah (ﷺ) lagged behind, and he mentioned this story. He said: We came to the people while Abdur-Rahman ibn Awf was leading them in the Subh (fajr) prayer. When he saw the Prophet (ﷺ), he wanted to step back, but the Prophet (ﷺ) signaled to him to continue. He said: So I and the Prophet (ﷺ) prayed one rak'ah behind him. When he gave the taslim, the Prophet (ﷺ) stood up and prayed the rak'ah that he had missed, and did not add anything to it.
Abu Dawud said: Abu Sa'id al-Khudri, Ibn al-Zubair, and Ibn 'Umar used to say: Whoever misses a rak'ah of the prayer, he must perform the two prostrations of forgetfulness.