God did not send his people into war on only a prayer. they were trained and had weapons.
Just something for you to ponder...
2Ch 20:1 It came to pass after this also, that the children of Moab, and the children of Ammon, and with them other beside the Ammonites, came against Jehoshaphat to battle.
2Ch 20:2 Then there came some that told Jehoshaphat, saying, There cometh a great multitude against thee from beyond the sea on this side Syria; and, behold, they be in Hazazontamar, which is Engedi.
2Ch 20:3 And Jehoshaphat feared, and set himself to seek the LORD, and proclaimed a fast throughout all Judah.
2Ch 20:4 And Judah gathered themselves together, to ask help of the LORD: even out of all the cities of Judah they came to seek the LORD.
2Ch 20:5 And Jehoshaphat stood in the congregation of Judah and Jerusalem, in the house of the LORD, before the new court,
2Ch 20:6 And said, O LORD God of our fathers, art not thou God in heaven? and rulest not thou over all the kingdoms of the heathen? and in thine hand is there not power and might, so that none is able to withstand thee?
2Ch 20:7 Art not thou our God, who didst drive out the inhabitants of this land before thy people Israel, and gavest it to the seed of Abraham thy friend for ever?
2Ch 20:8 And they dwelt therein, and have built thee a sanctuary therein for thy name, saying,
2Ch 20:9 If, when evil cometh upon us, as the sword, judgment, or pestilence, or famine, we stand before this house, and in thy presence, (for thy name is in this house,) and cry unto thee in our affliction, then thou wilt hear and help.
2Ch 20:10 And now, behold, the children of Ammon and Moab and mount Seir, whom thou wouldest not let Israel invade, when they came out of the land of Egypt, but they turned from them, and destroyed them not;
2Ch 20:11 Behold, I say, how they reward us, to come to cast us out of thy possession, which thou hast given us to inherit.
2Ch 20:12
O our God, wilt thou not judge them? for we have no might against this great company that cometh against us; neither know we what to do: but our eyes are upon thee.
2Ch 20:13 And all Judah stood before the LORD, with their little ones, their wives, and their children.
2Ch 20:15 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 yours, but God's.
2Ch 20:16 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.
2Ch 20:17 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.
2Ch 20:18 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.
2Ch 20:20 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.
2Ch 20:21 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.
2Ch 20:22 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.
2Ch 20:23 For the children of Ammon and Moab stood up against the inhabitants of mount Seir, utterly to slay and destroy them: and when they had made an end of the inhabitants of Seir, every one helped to destroy another.
2Ch 20:24 And when Judah came toward the watch tower in the wilderness, they looked unto the multitude, and, behold, they were dead bodies fallen to the earth, and none escaped.
Maybe we ought to teach our troops to sing.