Sunan An-Nasai, Chapter: The Book of Purification

that Habib said: "I heard Abbad bin Tammim narrate from my grandmother - who was Umm Umarah bint Kab - that the Prophet (saw) performed Wudu, and he was brought a vessel in which there were two thirds of a Mudd." Shubah said: I remember that he washed his forearms and started rubbing them, and he wiped the inside of his ear, but I do not remember whether he wiped the outside of them." (Sahih)