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

2 Samuel 21:9

And he gave them into the hand of the Gabaonites, and they hanged them up to the sun in the mountain before the Lord: and they fell, even the seven together: moreover they were put to death in the days of harvest at the commencement, in the beginning of barley-harvest.

Read in other translations