Sunan an-Nasa'i 4022
سنن النسائي#4022SahihIt was narrated that 'Arfajah said:"I heard the Messenger of Allah [SAW] say: 'After me there will be many calamities and much evil behavior. Whoever wants to create division among the Ummah (of Muhammad [SAW]) when they are all united, strike him with the sword
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 37:57