Musnad Ahmad 626:1

Isma'il narrated to us, Ayyub informed us, from Muhammad, from 'Amr ibn Wahb al-Thaqafi, who said: We were with al-Mughirah ibn Shu'bah, and he was asked: "Did anyone from this nation lead the Prophet, peace and blessings of Allah be upon him, in prayer other than Abu Bakr, may Allah be pleased with him?" He said: "Yes. We were with the Prophet, peace and blessings of Allah be upon him, on a journey. When it was the time before dawn, he struck the neck of my riding beast, and I thought he had a need, so I turned aside with him. We went until we were separated from the people, then he dismounted from his riding beast, then he went off and disappeared from my sight until I could not see him. He stayed for a long time, then he came and said: 'Do you have a need, O Mughirah?' I said: 'I have no need.' He said: 'Do you have water with you?' I said: 'Yes.' So I stood up to a water skin, or a leather water container, hanging on the back of the saddle, and I brought him water. I poured it upon him, and he washed his hands, and he washed them well." He said: "And I am in doubt whether he said: 'He rubbed them with dust or not.' Then he washed his face, then he went to uncover his arms, and he was wearing a Syrian cloak with narrow sleeves, so it was tight, and he brought his hands out from beneath it, and he washed his face and his hands." He said: "Does the hadith mention washing the face twice?" He said: "I do not know if it was like that or not. Then he wiped his forelock, and wiped over the turban, and wiped over the leather socks. We rode and caught up with the people, and the prayer had been established. 'Abd al-Rahman ibn 'Awf had stepped forward to lead them, and he had already prayed one rak'ah with them, and they were in the second. I went to inform him, but he forbade me. So we prayed the rak'ah that we caught, and we completed the rak'ah that we had missed."