Old Testament readings use the Septuagint , the Scripture the apostles quoted. Masoretic numbering shown for reference.Learn why
KJV

2 Chronicles 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.

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