He told that he heard God’s Messenger say, “If anyone comes to you when you are united under one man desiring to split you or cause parties in your community, kill him.”
‘Arfaja told that he heard God’s Messenger say, “Various corruptions will arise, so strike with the sword him who tries to cause separation in this people when they are united, whoever he be.”
‘Abdallah b. ‘Amr reported God’s Messenger as saying, “If anyone swears allegiance to an imam, giving him his hand in ratification and sincere agreement in his heart, he must obey him if he can. Then if another comes and contends with him, cut off that other one’s head.”
Abu Sa'id al-Khudri reported God’s Messenger as saying, “When allegiance is sworn to two caliphs kill the second of them.*
Muslim transmitted it.
* Some interpret ‘kill’ here as meaning to fight with. The tradition is directed against the possibility of two Caliphs holding power at the same time, even though the areas might be quite distinct.