¶And Jehoshaphat stood in the congregation of Judah and Jerusalem, in the house of the Lord, before the new court,
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?
He praises god some more and then lays out the history of Isreal, including a time when Isreal had the chance to destroy these same guys, but did not. He asks God for help because they are way outnumbered. 

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.

 Then someone namees Jahaziel prophesies:

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.
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.
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.

Upon hearing this Jehosephat bows and praises God. In fact, everyone does with loud voices. Then in the morning they go go down as the lord instructed, but here is what is cool--Jehosephat appoints singers to go before the army and to chant a mantra. 
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.

Guess what happens as soon as they start to sing this mantra and praise the Lord? 

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.
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.
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.

That's right. As the armies of Israel watched, all the enemy armies killed each other "and none escaped." (v 24)

It gets even better if you keep reading. They go out to check the dead bodies and find so much gold and jewels it takes them 3 days to bring it all back. Then on the 4th day they go home and do some more praising of god. This time with harps and trumpets. 

Then everything was peaceful and quiet. Wouldn't that be nice? 

30 So the realm of Jehoshaphat was quiet: for his God gave him rest round about.

What a cool story huh? I love that. Sometimes God tells me that it's not my battle to fight, and this is frustrating to me because I want to DO something. But I can do something. I can "set myself," (whatever that means, I'm sure it is different for you) and stand still and praise God.

He has so much power, and I think there is even more power in gratitude for his goodness, especially expressed out loud in words. If you haven't already, check out  my post, Mantras in the Scriptures and you wills see how almost every manta is a form of praising God and how much power there are in these words.