The Book on Government
33/1. Chapter:
The people follow the Quraish and the Caliphate belongs to the Quraish
Sahih Muslim
حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ " لاَ يَزَالُ أَمْرُ النَّاسِ مَاضِيًا مَا وَلِيَهُمُ اثْنَا عَشَرَ رَجُلاً " . ثُمَّ تَكَلَّمَ النَّبِيُّ صلى الله عليه وسلم بِكَلِمَةٍ خَفِيَتْ عَلَىَّ فَسَأَلْتُ أَبِي مَاذَا قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ " كُلُّهُمْ مِنْ قُرَيْشٍ " .
It has been reported on the authority of Jabir b. Samura who said: I heard the Messenger of Allah (ﷺ) say: The affairs of the people will continue to be conducted (well) as long as they are governed by twelve men. Then the Prophet (ﷺ) said words which were obscure to me. I asked my father: What did the Messenger of Allah (ﷺ) say? He said: All of the (twelve men) will be from the Quraish.
Reference : Sahih Muslim 1821bIn-book reference : Book 33, Hadith 6USC-MSA web (English) reference : Book 20, Hadith 4478