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

2 Chronicles 20:10

And now, behold, the children of Ammon, and Moab, and mount Seir, with regard to whom thou didst not permit Israel to pass through their border, when they had come out of the land of Egypt, (for they turned away from them, and did not destroy them;)—

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