Sayyiduna Jabir bin Samurah (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "The religion will remain established until the Hour is established, or until there have been twelve caliphs, all of them from Quraysh."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1796