It is narrated from Sayyiduna Mughirah bin Shu'bah (may Allah be pleased with him); he said: "The Messenger of Allah (peace and blessings be upon him) performed ablution and wiped over his leather socks, so I said: O Messenger of Allah! Did you forget? He (peace and blessings be upon him) said: Rather, it is you who forgot. My Lord has commanded me thus."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18125