Sahih al-Bukhari 7140
صحيح البخاري#7140Sahihحَدَّثَنَا 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 ".
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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 93:4