1 Chronicles 12:8, 37-38

Courageous men from the Gadites came over to David in the stronghold in the wilderness, men trained for war, who could handle shield and spear, whose faces were like the faces of lions, and who were swift as gazelles on the mountains.

From the other side [east] of the Jordan River, of [the tribes of] Reuben and Gad and the half-tribe of Manasseh, 120,000 men, armed with all kinds of weapons of war for the battle. All these, being men of war arrayed in battle formation, came to Hebron with a perfect (committed) heart to make David king over all Israel; and all the rest of Israel were also of one mind to make David king.