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 6171
'Umar b. Khattab reported: I heard Allah's Messenger (may peace be upon him) as saying: Worthy amongst the successors would be a person who would be called Uwais. He would have his mother (living with him) and he would have (a small) sign of leprosy. Ask him to beg pardon for you (from Allah).