It is narrated from Hazrat Abu Bakrah (may Allah be pleased with him) that once I saw the Prophet (peace and blessings be upon him) delivering a sermon on the pulpit when Hazrat Imam Hasan also came. The Prophet (peace and blessings be upon him) embraced him, placed his hand on his head, and said: "This son of mine is a leader, and Allah Almighty will bring reconciliation between two groups of Muslims through him."
Hadith Referenceمسند احمد / أول مسند البصريين / 20499
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 2704، وهذا إسناده ضعيف، مؤمل وابن جدعان ضعيفان، لكنهما توبعا