Sahih Muslim
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-Fadail Al-Sahabah)
Book Number: 031 / Hadith Number: 5962
Abdullah b. Ja'a'far reported that when Allah's Messenger (may peace be upon him) came back from a journey he met us. Once he met me, Hasan or Husain, and he mounted one of us before him and the other one behind him until we entered Medina.