Judges 10:9, 17-18

The Ammonites also crossed to the west side of the Jordan and attacked Judah, Benjamin, and Ephraim. The Israelites were in great distress.

At that time the armies of Ammon had gathered for war and were camped in Gilead, and the people of Israel assembled and camped at Mizpah. The leaders of Gilead said to each other, “Whoever attacks the Ammonites first will become ruler over all the people of Gilead.”