Observe the astonishing grace of the Lord manifested upon this occasion. It was instant, it was immediate; similar to that of Daniel's vision. At the beginning of the supplication, the commandment then came forth to Daniel. And here, while Jehoshaphat was speaking, the Lord answered. Daniel 9:19-21; Isaiah 65:24. And observe further, by whom did God vouchsafe to speak? - Even by a poor Levite, Jahaziel. The humblest instrument is sufficient, when the Lord is pleased to work. And remark further, how sure the promise is, Tomorrow shall bring forward their deliverance. And to decide from whom, and by whom the blessing comes; God himself will fight the battle for them; like another Moses, the direction is, Stand still and see the salvation of the Lord. Exodus 14:13.
2 Chronicles 20:14-17
14 Then upon Jahaziel the son of Zechariah, the son of Benaiah, the son of Jeiel, the son of Mattaniah, a Levite of the sons of Asaph, came the Spirit of the LORD in the midst of the congregation;
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 cliffb 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.