Sayyiduna Abu Bakrah (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) was delivering a sermon when Sayyiduna al-Hasan bin Ali (may Allah be pleased with him) climbed up to him (on the pulpit). The Prophet (peace and blessings be upon him) embraced him and said: "This son of mine is a leader (sayyid), and perhaps Allah, the Mighty and Majestic, will bring about reconciliation through him between two groups of the Muslims."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2575