When it’s time for war, even the unrighteous want God on their side. Once it became clear that the Benjamites were not going to surrender the criminals, the Israelites went to Bethel and asked God’s guidance. The priest told them that Judah should go up first and that is what they did. After losing a great number of men, they went back to the priest and wept before God. They asked if they should really be fighting their fellow Israelites? The Lord told them to go up again, and once again the Benjamites handed them a great defeat. That day they fasted until evening and presented burnt offerings and fellowship offerings to the Lord. Once again they asked the Lord if they were doing what they should and the Lord told them to go to battle once again and this time he would give them victory.
As has been established, at this time in their history, the nation of Israel was not a righteous people, yet they made offerings that signified commitment and devotion to the Lord. What is conspicuously absent is any sin offering signifying the commitment to repentance and righteousness. They wanted God on their side; when they entered battle they wanted the Lord to be with them. However, they had not arrived, and would not arrive, at the place they recognize their own sin and their own need for forgiveness. They did not recognize that victory does not come from God being on our side; victory comes when we are on the side of God.
The next day they went to battle and God gave them complete victory. God did not give them victory because he was on their side; God gave the Israelites victory because he used them and their anger to punish the men of Gibeah for their wickedness. The Israelites assumed God would be on their side no matter what they chose to do next. They were wrong, God is only on our side when we choose to live at his side.