Musnad Ahmad 32:1442

Yunus and Hassan ibn Musa narrated to us, they said: Hammad ibn Salamah narrated to us, from Thabit al-Bunani, from Anas ibn Malik, that a man asked the Messenger of Allah, peace and blessings of Allah be upon him: "When will the Hour be established?" There was a boy from the Ansar with him who was called Muhammad. The Messenger of Allah, peace and blessings of Allah be upon him, said to him: "If this boy lives, it is likely that he will not reach old age until the Hour is established."