The heart to the Lord

Judges 20:1-26
"Speak up and give your verdict", the Levite said to all Israelites.
The Israelites went up and wept before the Lord until evening, and they inquired of the Lord first time defeated. Second times, all the people, went up to Bethel, and there they sat weeping  before the Lord. they fasted that day until evening and presented burnt offerings and fellowship offerings to the Lord.
The details of the battle recall the strategy at Ai.
Why?
The Levite asked for the justice and verdict for this events from whole Israelites. Basically there is justice among Israelites in stead of Benjamin.
Before the war under the name of the Lord, it have to scarify themselves and pray to the Lord, devote the burnt offering and fellowship offering. Fasting is needed either.
How?
Keep clean heart and humble myself before the Lord. But the Lord like the man who confess his sins and return to God.