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

Exodus 18:21

And do thou look out for thyself out of all the people able men, fearing God, righteous men, hating pride, and thou shalt set over the people captains of thousands and captains of hundreds, and captains of fifties, and captains of tens.

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