Musnad Ahmad 25:1116

Abu al-Walid narrated to us, Abu 'Awanah narrated to us, from 'Ata', from Sa'id ibn Jubayr, from Ibn 'Abbas, who said: The Messenger of Allah, peace and blessings of Allah be upon him, wiped over the khuffayn (leather socks). So ask those who claim that the Prophet, peace and blessings of Allah be upon him, wiped: Was it before the revelation of [Surah] al-Ma'idah, or after [Surah] al-Ma'idah? By Allah, he did not wipe after [Surah] al-Ma'idah. And for me to wipe over the back of a camel in the wilderness is more beloved to me than to wipe over them.