Sahih Bukhari
Judgments (Ahkaam)
Volume: 009 / Book Number: 089 / Hadith Number: 329
Narrated Jabir bin Samura:
I heard the Prophet saying, "There will be twelve Muslim rulers (who will rule all the Islamic world)." He then said a sentence which I did not hear. My father said, "All of them (those rulers) will be from Quraish."