1 Chronicles 12:8, 37, 38

Some Gadites defected to David at his stronghold in the wilderness. They were brave warriors, ready for battle and able to handle the shield and spear. Their faces were the faces of lions, and they were as swift as gazelles in the mountains.

and from east of the Jordan, from Reuben, Gad and the half-tribe of Manasseh, armed with every type of weapon—120,000.

All these were fighting men who volunteered to serve in the ranks. They came to Hebron fully determined to make David king over all Israel. All the rest of the Israelites were also of one mind to make David king.