2 Chronicles 20:21-23

After consulting the people, Jehoshaphat appointed men to sing to the LORD and to praise him for the splendor of his holiness as they went out at the head of the army, saying: “Give thanks to the LORD, for his love endures forever.” As they began to sing and praise, the LORD set ambushes against the men of Ammon and Moab and Mount Seir who were invading Judah, and they were defeated. The Ammonites and Moabites rose up against the men from Mount Seir to destroy and annihilate them. After they finished slaughtering the men from Seir, they helped to destroy one another.