Musannaf Ibn Abi Shaybah

Hazrat Abu Abdur Rahman says that I was sitting with Hazrat Abdur Rahman bin Awf when Hazrat Bilal passed by us. We asked him about wiping over leather socks (khuffs), so he said that when the Holy Prophet (peace and blessings be upon him) would return after relieving himself, we would present water to him. He would perform ablution, then wipe over his leather socks and turban.