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

Isaiah 50:1

Thus saith the Lord, Of what kind is your mother's bill of divorcement, by which I put her away? or to which debtor have I sold you? Behold, ye are sold for your sins, and for your iniquities have I put your mother away.

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