عن عرفجة رضي الله عنه قال: سمعت رسول الله صلى الله عليه وسلم يقول: "من أتاكم وأمرُكُم جَمِيْعٌ على رجل واحد، يُريد أن يَشُقَّ عَصَاكُم، أو يُفَرِّقَ جَمَاَعَتَكُم، فاقتُلُوهُ". [صحيح] - [رواه مسلم] المزيــد ...
‘Arfajah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "If someone comes to you seeking to undermine your solidarity or disrupt your unity when you have agreed on a man (as your leader), kill him." Sahih/Authentic. - [Muslim]
This Hadīth is about fighting rebels who want to divide the Muslims after they have unified and agreed on a ruler. It also indicates that if the Muslims have agreed to appoint a specific caliph or ruler and someone wants to depose the man they have agreed on, it is incumbent upon them to resist this person, even if that results in killing him, in order to avert the harm and prevent the bloodshed of Muslims.
It is obligatory to listen and obey the Muslim ruler, and it is prohibited to revolt against him.
If someone revolts against the ruler who is accepted by Muslims at large, he should be killed, regardless of his status or nobility.
According to the Hadīth’s apparent meaning, the ruling applies to the case when revolt is launched by either one person or a group of people; they should be killed. However, if the group is powerful, and its members revolt against the ruler is based on a reasonable cause, they are deemed aggressors. But if there is no such cause and they merely want to seize power, then they should be treated like highway robbers.
It urges Muslims to unite and keep away from disunity and dissension.