‏الإمارة : Hadeeth No:4568 It has been narrated on the authority of Aba Sa'id al-Khudri that the Messenger of Allaah (sallAllaahu alayhi wa sallam) said: When oath of allegiance has been taken for two caliphs, kill the one for whom the oath was taken later....

‏الإيمان : Hadeeth No:62 It is narrated on the authority of Sufyan b. 'Abdulla al-Thaqafi that he said: I asked the Messenger of Allaah to tell me about Islam a thing which might dispense with the necessity of my asking anybody after you. In the hadith of Abu Usama the (words) are: other than you. He (the Prophet) remarked:...