It has been narrated on the authority of Jabir b. Samura who said: I heard the Messenger of Allaah (sallAllaahu alayhi wa sallam) say: Islam will continue to be triumphant until there have been twelve Caliphs. Then the Prophet (sallAllaahu alayhi wa sallam) said something which I could not understand. I asked my father: What did he say? He said: He has said that all of them (twelve Caliphs) will be from the Quraish.