The Prophet (ﷺ) said, "The Israelis used to be ruled and guided by Prophet's. Whenever a Prophet (ﷺ) died, another would take over his place. There will be no Prophet (ﷺ) after me, but there will be caliphs who will increase in number." The people asked, O Allâh's Messenger (ﷺ)! What do you order us (to do)?" He said, "Obey the one who will be given the Bai'a-- pledge first. Fulfil their (i.e. the caliphs ') rights, for Allâh will ask them about (any short-comings) in ruling those whom Allâh has put under their guardianship. [4:661-O.B]