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 6060
Anas reported (that his mother) Umm Sulaim said (to the Holy Prophet) Allah's Messenger, here is your servant Anas. The rest of the hadith is the same.