The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)
Muslim :: Book 31 : Hadith 5913
Amir b Sa'd b. Abi Waqqas reporte (l on the authority of his father that Allah's Messenger (may peace be upon him) addressing 'All said: You are in the same position with relation to me as Aaron- (Harun) was in relation to Moses but with (this explicit difference) that there is no prophet after me. Sa'd said: I had an earnest desire to hear it directly from Sa'd, so I met him and narrated to him what (his son) Amir had narrated to me, whereupon he said: Yes, I did hear it. I said: Did you hear it yourself? Thereupon he placed his fingers upon his ears and said: Yes, and if not, let both my ears become deaf.