Musnad Ahmad 141:2

'Affan narrated to us, Yahya bin Sa'id narrated to us, he said: Abu Ja'far 'Umayr bin Yazid narrated to me, he said: Al-Harith bin Fudayl and 'Umarah bin Khuzaymah bin Thabit narrated to me, from 'Abd al-Rahman bin Abi Qurad, who said: I went out with the Messenger of Allah, peace and blessings of Allah be upon him, for Hajj. He said: He stopped at a place and came out from relieving himself, so I followed him with a water skin—or a cup. The Messenger of Allah, peace and blessings of Allah be upon him, used to go far away when he wanted to relieve himself. I sat for him on the path until the Messenger of Allah, peace and blessings of Allah be upon him, returned. I said to him: "O Messenger of Allah, the ablution (wudu)." The Messenger of Allah, peace and blessings of Allah be upon him, came toward me, and the Messenger of Allah, peace and blessings of Allah be upon him, poured water onto his hand and washed it. Then he inserted his hand and cupped it, and poured onto one hand. Then he wiped his head. Then he took a handful of water with his hand and struck it upon the top of his foot, and wiped over his foot with his hand. Then he came and led us in the Dhuhr prayer.