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 5952
Abu Huraira reported: I went along with Allalh's Messenger (may peace be upon him) at a time during the day but he did not talk to me and I did not talk to him until he reached Bazar of Banfi Qainuqal. He came back to the tent of Fatima and said: Is the little chap (meaning Hasan) there? We were under the impression that his mother had detained him in order to bathe him and dress him and garland him with a sweet garland. Not much time had passed that he (Hasan) came running until both of them embraced each other, thereupon Allah's Messenger (may peace be upon him) said: O Allah, I love him; love him Thou and love one who loves him (Hasan).