(50) باب مَا ذُكِرَ عَنْ بَنِي إِسْرَائِيلَ
Narrated Abu Huraira:
The Prophet (ﷺ) said, "The Israelis used to be ruled and guided by prophets: Whenever a prophet died, another would take over his place. There will be no prophet after me, but there will be Caliphs who will increase in number." The people asked, "O Allah's Messenger (ﷺ)! What do you order us (to do)?" He said, "Obey the one who will be given the pledge of allegiance first. Fulfil their (i.e. the Caliphs) rights, for Allah will ask them about (any shortcoming) in ruling those Allah has put under their guardianship."
Reference: Sahih al-Bukhari 3455
In-book reference: Book 60, Hadith 122
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 55, Hadith 661