2 Chronicles 20:15 in the King James Version
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.
Context
14 Then the LORD’s Spirit came on Jahaziel the son of Zechariah, the son of Benaiah, the son of Jeiel, the son of Mattaniah, the Levite, of the sons of Asaph, in the middle of the assembly;
15 and he said, “Listen, all Judah, and you inhabitants of Jerusalem, and you, King Jehoshaphat. The LORD says to you, ‘Don’t be afraid, and don’t be dismayed because of this great multitude; for the battle is not yours, but God’s.
16 Tomorrow, go down against them. Behold, they are coming up by the ascent of Ziz. You will find them at the end of the valley, before the wilderness of Jeruel.