2 Chronicles 20:19-22

19Then the Levites of the children of the Kohathites and of the children of the Korahites stood up to praise the Lord God of Israel with voices loud and high.

20So they rose early in the morning and went out into the Wilderness of Tekoa; and as they went out, Jehoshaphat stood and said, “Hear me, O Judah and you inhabitants of Jerusalem: Believe in the Lord your God, and you shall be established; believe His prophets, and you shall prosper.”

21And 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.”

22Now 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.