2 Chronicles 20:15-22

and he said, Hearken ye, all Judah, and ye inhabitants of Jerusalem, and thou king Jehoshaphat, Thus saith the LORD unto you, Be not afraid nor dismayed by reason of this great multitude; for the battle is not your's, but God's. To morrow go ye down against them: behold, they come up by the cliff of Ziz; and ye shall find them at the end of the brook, before the wilderness of Jeruel. Ye shall not need to fight in this battle: set yourselves, stand ye still, and see the salvation of the LORD with you, O Judah and Jerusalem: fear not, nor be dismayed; to morrow go out against them: for the LORD will be with you. And Jehoshaphat bowed his head with his face to the ground: and all Judah and the inhabitants of Jerusalem fell before the LORD, worshipping the LORD. And the Levites, of the children of the Kohathites, and of the children of the Korhites, stood up to praise the LORD God of Israel with a loud voice on high. And they rose early in the morning, and went forth into the wilderness of Tekoa: and as they went forth, Jehoshaphat stood and said, Hear me, O Judah, and ye inhabitants of Jerusalem; Believe in the LORD your God, so shall ye be established; believe his prophets, so shall ye prosper. And when he had consulted with the people, he appointed singers unto the LORD, and that should praise the beauty of holiness, as they went out before the army, and to say, Praise the LORD; for his mercy endureth for ever. And when they began to sing and to praise, the LORD set ambushments against the children of Ammon, Moab, and mount Seir, which were come against Judah; and they were smitten.