The Messenger of Allah ﷺ said, "Whoever draws the sword against us is not one of us."
قال حدثنا بهز قال حدثنا عكرمة بن عمار
قال رسول الله ﷺ من سل علينا السيف فليس منا
Its isnad is sahih. It is found in Muslim 1/98, no. 99, in the book of Iman, the saying of the Prophet ﷺ, "Whoever takes up arms against us." Also in Ibn Abu Shayba 10/121, no. 8979, in the book of Hudud, concerning a man who strikes another with a sword and it turns back on him. And in Tabarani's Al-Kabir 7/19, no. 6249.