2 Chronicles 20:21-22

21And when he had consulted with the people, he appointed singers to the LORD, and that should praise the beauty of holiness, as they went out before the army, and to say, Praise the LORD; for his mercy endureth for ever.1 22And when they began to sing and to praise, the LORD set ambushes against the children of Ammon, Moab, and mount Seir, who were come against Judah; and they were smitten.234