John Wesley on 2 Chronicles 20:21

Consulted - Jehoshaphat called a counsel of war, and it was resolved, to appoint singers to go out before the army, who had nothing to do, but to praise God, to praise his holiness, which is his beauty, to praise him as they did in the temple, that beauty of holiness. By this strange advance to the field of battle, Jehoshaphat shewed his firm reliance on the word of God, which enabled him to triumph before the battle, to animate his own men and confound the enemy.