Sunan Abi Dawud
Hadith #4662
Narrated AbuBakrah: The Messenger of Allah (ﷺ) said to al-Hasan ibn Ali. This son of mine is a Sayyid (chief), and I hope Allah may reconcile two parties of my community by means of him. Hammad's version has: And perhaps Allah may reconcile two large parties of Muslims by means of him