Sayyiduna Abu Bakrah (may Allah be pleased with him) narrates: I saw the Messenger of Allah (peace and blessings be upon him) on the pulpit, with Sayyiduna al-Hasan bin Ali (may Allah be pleased with him) at his side. He would look at the Messenger of Allah (peace and blessings be upon him) once, and the Messenger of Allah (peace and blessings be upon him) would look at him once, and he was saying: "This son of mine is a leader (sayyid), and perhaps Allah will bring about reconciliation through him between two groups of the Muslims."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2577