Urwah, the son of Sayyiduna al-Mughirah bin Shu'bah (may Allah be pleased with him), narrates from his father, from the Prophet (peace and blessings be upon him), that he (peace and blessings be upon him) went out to relieve himself, and Sayyiduna al-Mughirah (may Allah be pleased with him) followed him with a vessel of water. He poured water for him when he had finished relieving himself, then he (peace and blessings be upon him) performed ablution and wiped over his leather socks.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1280