Sahih Muslim 4798
صحيح مسلم#4798SahihIt has been narrated (through a still different chain of transmitters) on the Same authority (i. e. 'Arfaja) who said similarly-but adding:" Kill all of them." I heard the Messenger of Allah (ﷺ) say: When you are holding to one single man as your leader, you should kill who seeks to undermine your solidarity or disrupt your unity
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 33:95