Abu Wahb said that he heard Sayyiduna Abu Hurayrah (may Allah be pleased with him) say: The Messenger of Allah (peace and blessings be upon him) said to me: "Help me with ablution." I brought him water; he (peace and blessings be upon him) cleaned himself, then put his hand into the earth and rubbed it, then he (peace and blessings be upon him) washed that hand and performed ablution, and also wiped over his leather socks. I said: You performed ablution and did not wash your feet? He (peace and blessings be upon him) said: "I put them on after performing ablution."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 522