Musnad Ahmad 626:23

Ibrahim ibn Abi al-Abbas narrated to us, Abd al-Rahman ibn Abi al-Zinad narrated to us, from Abi al-Zinad, from Urwah, who said: Al-Mughirah said: "I saw the Messenger of Allah, may Allah bless him and grant him peace, wiping over the tops of the khuffayn (leather socks)." Abdullah said: My father said: Surayj narrated it to us, and al-Hashimi also.