Judges 10:9, 17-18

The Ammonites also crossed the Jordan and fought against the tribes of Judah, Benjamin, and Ephraim, leaving Israel distressed.

Then the Ammonites mustered an army and encamped in Gilead, while the Israelites rallied together, and they encamped at Mizpah. The commanders of the people of Gilead said to one another, “Whoever starts the fight against the Ammonites, we’ll make him our leader.”