Verses with the word harrows in the Old Testament (2 verses):

2 Samuel 12:31
And he brought forth the people that were therein, and put them under saws, and under harrows of iron, and under axes of iron, and made them pass through the brick-kiln: and thus did he unto all the cities of the children of Ammon. So David and all the people returned unto Jerusalem.

1 Chronicles 20:3
And he brought out the people that were in it, and cut them with saws, and with harrows of iron, and with axes. Even so dealt David with all the cities of the children of Ammon. And David and all the people returned to Jerusalem.