Musnad Ahmad 32:367

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from ‘Ali Abu al-Asad, who said: Bukayr ibn Wahb al-Jazari narrated to me, saying: Anas ibn Malik said to me: I will narrate to you a hadith that I do not narrate to everyone. Indeed, the Messenger of Allah (may Allah bless him and grant him peace) stood at the door of the house while we were inside it, and he said: "The Imams are from Quraysh. They have a right over you, and you have a right over them equal to that, provided that if they are asked for mercy, they show mercy; if they make a covenant, they fulfill it; and if they judge, they act justly. Whoever among them does not do that, then upon him is the curse of Allah, the angels, and all of mankind."