Al-Sha'bi narrates that Sayyiduna Jabir (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say during the Farewell Hajj: "The affair of this Ummah will remain calm against those who oppose it until there have been twelve amirs over you." Then he (peace and blessings be upon him) said something that I did not hear, so I asked my father, who was closer to him than I was: What did he (peace and blessings be upon him) say? He said: He said: "All of them will be from Quraysh."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1787