Sahih al-Bukhari 7140
صحيح البخاري#7140SahihNarrated 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
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 93:4