2 Chronicles 20:19

16 Go down against them tomorrow: see, they are coming up by the slope of Ziz; at the end of the valley, before the waste land of Jeruel, you will come face to face with them.

17 There will be no need for you to take up arms in this fight; put yourselves in position, and keep where you are, and you will see the salvation of the Lord with you, O Judah and Jerusalem: have no fear and do not be troubled: go out against them tomorrow, for the Lord is with you.

18 Then Jehoshaphat went down with his face to the earth, and all Judah and the people of Jerusalem gave worship to the Lord, falling down before him.

19 And the Levites, the children of the Kohathites and the Korahites, got to their feet and gave praise to the Lord, the God of Israel, with a loud voice.

20 And early in the morning they got up and went out to the waste land of Tekoa: and when they were going out, Jehoshaphat took his station and said to them, Give ear to me, O Judah and you people of Jerusalem: have faith in the Lord your God and you will be safe; have faith in his prophets and all will go well for you.

21 And after discussion with the people, he put in their places those who were to make melody to the Lord, praising him in holy robes, while they went at the head of the army, and saying, May the Lord be praised, for his mercy is unchanging for ever.

22 And at the first notes of song and praise the Lord sent a surprise attack against the children of Ammon and Moab and the people of Mount Seir, who had come against Judah; and they were overcome.