Musnad Ahmad 33:859

'Ali ibn 'Asim narrated to us, from Yazid—meaning Ibn Abi Ziyad—from Salim ibn Abi al-Ja'd, from Jabir ibn 'Abdullah, from the Prophet, peace and blessings of Allah be upon him, who said: "A mudd of water suffices for wudu, and a sa' for janabah." A man said: "It is not enough for me." Jabir said: "It sufficed for one who was better than you, and had more hair: the Messenger of Allah, peace and blessings of Allah be upon him."