The Caliphate will remain among the Quraish even if only two persons are left (on the earth),
Sahih Muslim Book 33, Hadith 4
← Previous Hadith People are the followers of Quraish in good as well as evil (i. e. in the customs of Islamic as well as pre-Islamic times).

Sahih Muslim Book 33, Hadith 3 Next Hadith → I joined the company of the Prophet (ﷺ) with my father and I heard him say: This Caliphate will not end until there have been twelve Caliphs among them. The narrator said: Then he (the Holy Prophet) said something that I could not follow. I said to my father: What did he say? He said: He has said: All of them will be from the Quraish.

Sahih Muslim Book 33, Hadith 5