2 Chronicles 20:21-22

21Then he consulted with the people and appointed some to sing for the Lord and some to praise the splendor of his holiness. When they went out in front of the armed forces, they kept singing: Give thanks to the Lord, for his faithful love endures forever.

22The moment they began their shouts and praises, the Lord set an ambush against the Ammonites, Moabites, and the inhabitants of Mount Seir who came to fight against Judah, and they were defeated.