They went up, wept before the Lord until evening, and inquired of Him: "Should we again fight against our brothers the Benjaminites?" And the Lord answered: "Fight against them."
On the second day the Israelites advanced against the Benjaminites.
That same day the Benjaminites came out from Gibeah to meet them and slaughtered an additional 18,000 Israelites on the field; all were armed men.
The whole Israelite army went to Bethel where they wept and sat before the Lord. They fasted that day until evening and offered burnt offerings and fellowship offerings to the Lord.
Then the Israelites inquired of the Lord. In those days, the ark of the covenant of God was there,
and Phinehas son of Eleazar, son of Aaron, was serving before it. The Israelites asked: "Should we again fight against our brothers the Benjaminites or should we stop?" The Lord answered: "Fight, because I will hand them over to you tomorrow."
So Israel set up an ambush around Gibeah.
On the third day the Israelites fought against the Benjaminites and took their battle positions against Gibeah as before.
Then the Benjaminites came out against the people and were drawn away from the city. They began to attack the people as before, killing about 30 men of Israel on the highways, one of which goes up to Bethel and the other to Gibeah through the open country.
The Benjaminites said, "We are defeating them as before." But the Israelites said, "Let's flee and draw them away from the city to the highways."
So all the men of Israel got up from their places and took their battle positions at Baal-tamar, while the Israelites in ambush charged out of their places west of Geba.
References for Judges 20:33