2 Chronicles 20

When the combined armies of the Ammonites, Moabites, and Meunites attack Judah, Jehoshaphat proclaims a nationwide fast and leads the people in prayer in the Temple court. God answers through the prophet Jahaziel, assuring them, "The battle is not yours, but God’s." The next morning, Jehoshaphat sends the singers out ahead of the army. As the singers praise God, the Ammonites, Moabites, and Meunites turn on each other and destroy themselves. Judah arrives to find a deserted battlefield and immense plunder.