2 Chronicles 20:21-23

When he had consulted with the people, he appointed those who sang to the LORD and those who praised Him in holy attire, as they went out before the army and said, “Give thanks to the LORD, for His lovingkindness is everlasting.” When they began singing and praising, the LORD set ambushes against the sons of Ammon, Moab and Mount Seir, who had come against Judah; so they were routed. For the sons of Ammon and Moab rose up against the inhabitants of Mount Seir destroying them completely; and when they had finished with the inhabitants of Seir, they helped to destroy one another.