Charles Ellicott Commentary 1 Chronicles 20:3

"And he brought forth the people that were therein, and cut [them] with saws, and with harrows of iron, and with axes. And thus did David unto all the cities of the children of Ammon. And David and all the people returned to Jerusalem." — 1 Chronicles 20:3 (ASV)

And he brought. —Better, “And the people that were in it he brought out, and sawed with the saw, and with the iron threshing-drags (Isaiah 41:15), and with the axes.”

Sawed. —The Hebrew is an old word, only found here. Samuel reads, by a change of one letter, “set them in,” or “among,” the saws, and so forth.

With the axes. —So Samuel. Our Hebrew text repeats the word “saw” in the plural, owing to a scribe’s error. The two words differ by a single letter. Samuel adds, “and made them pass through the brick-kiln,” or “Moloch’s fire” (2 Kings 23:10).

Even so dealt David. —Literally, And so David used to do. These cruelties were repeated at the taking of every Ammonite city. There is no need to attempt to palliate such revolting savagery; but according to the ideas of that age, it was only a glorious revenge. As David treated Ammon, so the Ammonites would have treated Israel, had the victory been theirs. (Compare their behaviour towards the Gileadites, Amos 1:13; compare also the atrocities of Assyrian conquerors, Hosea 10:14, and of the Babylonians, Psalms 137:7–9.)