Sahih al-Bukhari 7140
Book 93: Judgments (Ahkaam) · Narrated by Ibn `Umar
Arabic
حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، حَدَّثَنَا عَاصِمُ بْنُ مُحَمَّدٍ، سَمِعْتُ أَبِي يَقُولُ، قَالَ ابْنُ عُمَرَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ يَزَالُ الأَمْرُ فِي قُرَيْشٍ مَا بَقِيَ مِنْهُمُ اثْنَانِ ".
English translation
Narrated Ibn `Umar:Allah's Messenger (ﷺ) said, "This matter (caliphate) will remain with the Quraish even if only two of them were still existing
Reference: Sahih al-Bukhari 7140, Book of Judgments (Ahkaam). English translation by Dr. Muhammad Muhsin Khan.