Musnad Ahmad 32:447

Bahz narrated to us, Hammad ibn Salamah narrated to us, he said: Ubayd Allah ibn Abi Bakr informed us, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) gathered his fingertips and tapped them on the ground, then said: "This is the son of Adam." And he gestured with his hand behind that and said: "And this is his appointed time (ajal)." Then he gestured in front of him and said: "And there is his hope (amal)." [He repeated this] three times.