Musnad Ahmad 830:20

Sufyan narrated to us, from Abu Musa—and it is said of him: Isra’il—he said: I heard Al-Hasan, he said: I heard Abu Bakrah—and Sufyan said once: from Abu Bakrah—I saw the Messenger of Allah, peace and blessings of Allah be upon him, on the pulpit, and Al-Hasan was with him. He would turn toward the people once, and toward him once, and he would say: "Indeed, this son of mine is a leader, and perhaps Allah will reconcile through him between two groups of the Muslims."