2 Chronicles 20:20-23

Early in the morning they left for the Desert of Tekoa. As they set out, Jehoshaphat stood and said, ‘Listen to me, Judah and people of Jerusalem! Have faith in the LORD your God and you will be upheld; have faith in his prophets and you will be successful.’ After consulting the people, Jehoshaphat appointed men to sing to the LORD and to praise him for the splendour of his holiness as they went out at the head of the army, saying: ‘Give thanks to the LORD, for his love endures for ever.’ As they began to sing and praise, the LORD set ambushes against the men of Ammon and Moab and Mount Seir who were invading Judah, and they were defeated. The Ammonites and Moabites rose up against the men from Mount Seir to destroy and annihilate them. After they finished slaughtering the men from Seir, they helped to destroy one another.