2 Chronicles 20:19-22

19Levites, from the sons of Kohath and the sons of Korah, stood up to praise Adonai, the God of Israel, with a very loud voice.

20Early in the morning they arose and went out into the wilderness of Tekoa. As they went forth, Jehoshaphat stood and said, “Listen to me, O Judah and inhabitants of Jerusalem! Believe in Adonai your God and you will be confirmed. Trust in His prophets and you will succeed.”

21After consulting with the people, he appointed singers to Adonai praising the splendor of His holiness, as they went out before the army saying, “Praise Adonai, `for His mercy endures forever.”

22As they began singing and praising, Adonai set ambushes against the children of Ammon, Moab, and Mount Seir who had come against Judah, and they were defeated.