Musnad Ahmad 626:109

Waki’ narrated to us, Yunus bin Abi Ishaq narrated to us, he heard it from al-Sha’bi, who said: ‘Urwah bin al-Mughirah testified to me regarding his father, that his father testified to him regarding the Messenger of Allah (ﷺ), that he was on a journey, so he made his camel kneel, and his companions made their camels kneel. He said: The Prophet (ﷺ) went out to relieve himself, then he came back. I brought him a water skin, and he was wearing a Roman jubbah (outer garment) with tight sleeves. He went to take his hands out, but they were too tight, so he took them out from under the jubbah. He said: Then I poured water for him, and he performed wudu. When he reached the khuffayn (leather socks), I reached down to remove them, but he said: "No, for I inserted them while they were in a state of purity." He said: So he performed wudu and wiped over them. Al-Sha’bi said: So ‘Urwah testified to me regarding his father, who testified to him regarding the Prophet (ﷺ).