Jehoshaphat sends out judges and teachers again, with a charge to warn all the people away from sin as they judge.
Moabites and Ammonites gather to fight against Judah. Jehoshaphat assembles the people and leads a prayer to God for help. A prophet responds that God will fight for them. When Jehoshaphat leads the army out in the morning, he sends the choir ahead, singing. God causes the enemy to fight each other until they are destroyed, and Judah doesn't have to lift a finger except to take away the spoil.
Jehoshaphat doesn't learn his lesson about allying with unbelief. He allies with Ahaziah, Ahab's son in a sailing expedition, and the ships are wrecked before getting to their first port.
How this is about Jesus
He went about to all the cities of Israel teaching in the synogogues.
Trust God to fight for us, as we sing His praise.