Hadith : Shaitan is with the one who splits away from the Ummah, running with him.

It was narrated that 'Arfajah bin Shuraih Radi Allahu Anhu he said: "I saw the Prophet Sallallahu Alaihi Wasallam on the Minbar addressing the people. He Sallallahu Alaihi Wasallam said: After me there will be many calamities and much evil behavior.

Whoever you see splitting away from the Jamaah or trying to create division among the Ummah of Muhammad Sallallahu Alaihi Wasallam , then kill him, for the Hand of ALLAh is with the Jamaah, and the Shaitan is with the one who splits away from the Ummah, running with him.

Sunan Nasaii, Vol 5, 4025 - Sahih

 

Abu Dharr Radi Allahu Anhu reported from the Prophet Peace be upon him that, "Two are better than one, and three better than two; so stick to the Jamaah for verily Allah, Most Great and Glorious, will only unite my nation on guidance." 

Masnad Ahmed , 20776 – Hasan