Musnad Ahmad 32:1906

'Affan narrated to us, Hammad—meaning Ibn Salamah—narrated to us, Thabit informed us, from Anas ibn Malik, that a man said: "O Messenger of Allah, when will the Hour be established?" And there was with him a young boy from the Ansar who was called Muhammad. He said: "If this one lives, it is possible that old age will not overtake him until the Hour is established."