(a) Urwah bin al-Mughirah bin Shu'bah (may Allah have mercy on him) relates that al-Mughirah bin Shu'bah (may Allah be pleased with him) went on a military expedition with the Messenger of Allah (peace and blessings be upon him). Then he mentioned the complete hadith about the ablution of the Messenger of Allah (peace and blessings be upon him) and his wiping over the leather socks. He said: Then he came back, and Sayyiduna al-Mughirah (may Allah be pleased with him) said: I came with him until he (peace and blessings be upon him) found that the people had put Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him) forward to lead the prayer. Abd al-Rahman bin Awf (may Allah be pleased with him) led them in prayer, and the Messenger of Allah (peace and blessings be upon him) caught only one rak'ah. He prayed the second rak'ah with the people, and when Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him) said the salam, he (peace and blessings be upon him) stood up to complete his prayer. The Muslims were alarmed when they saw this, and they began saying "Subhan Allah" (Allah is free of all imperfection) a great deal. When the Messenger of Allah (peace and blessings be upon him) had completed his prayer, he turned towards them and said: "You did well," or he said: "You have done what is right." He (peace and blessings be upon him) was pleased with them for having offered the prayer on time.
(b) In the narration of Ibn Jurayj (may Allah have mercy on him), Sayyiduna al-Mughirah (may Allah be pleased with him) said: I wanted to move Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him) back, but the Prophet (peace and blessings be upon him) said: "Leave him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3617