Judges 20:31-32

31When the men of Benjamin came out to attack, they were drawn away from the town. And as they had done before, they began to kill the Israelites. About thirty Israelites died in the open fields and along the roads, one leading to Bethel and the other leading back to Gibeah.

32Then the warriors of Benjamin shouted, “We’re defeating them as we did before!” But the Israelites had planned in advance to run away so that the men of Benjamin would chase them along the roads and be drawn away from the town.