Abu Huraira reported the Prophet (ﷺ) as saying, “The B. Isra’il were governed by the prophets, as often as one died another taking his place. There will be no prophet after me, but there will be numerous caliphs.” He was asked what command he had to give and replied, “Fulfil the oath of allegiance to each and give them their due for God will question them about what He asked them to guard.” (Bukhari and Muslim.)