Musnad Ahmad 25:769

Daud ibn Mihran narrated to us, Daud—meaning al-Attar—narrated to us, from Ibn Jurayj, from Ubayd Allah ibn Abi Yazid, from Ibn Abbas, who said: A man said: "How much [water] is sufficient for me for ablution (wudu)?" He said: "A mudd." He said: "How much is sufficient for me for the ritual bath (ghusl)?" He said: "A sa'." The man said: "It is not sufficient for me." He said: "May you have no mother! It was sufficient for one who was better than you: the Messenger of Allah, may Allah bless him and grant him peace."