Musnad Ahmad 626:93

Hashim ibn al-Qasim narrated to us, 'Abd al-'Aziz—meaning Ibn Abi Salamah—narrated to us, Sa'd ibn Ibrahim narrated to us, from Nafi' ibn Jubayr, from 'Urwah ibn al-Mughirah ibn Shu'bah, from his father, al-Mughirah, who said: "The Messenger of Allah (ﷺ) went for some of his needs, then he came, and I poured water for him. He washed his face, then he went to wash his forearms, but the sleeve of his jubbah (outer garment) was too tight for them. So, he brought them out from under the jubbah, washed them, and then wiped over his khuffayn (leather socks)."