II Chronicles 20:21-22

And when he had consulted with the people, he appointed those who should sing to the LORD, and who should praise the beauty of holiness, as they went out before the army and were saying: “Praise the LORD, For His mercy endures forever.” Now when they began to sing and to praise, the LORD set ambushes against the people of Ammon, Moab, and Mount Seir, who had come against Judah; and they were defeated.