Commentary on the Bible, by Adam Clarke, [1831], at sacred-texts.com
David sends a congratulatory message to Hanun, king of Ammon, Ch1 19:1, Ch1 19:2. He treats the messengers with great incivility, Ch1 19:3, Ch1 19:4. David is exasperated, but condoles with the degraded messengers, Ch1 19:5. The Ammonites prepare for war, and hire thirty-two thousand chariots, and besiege Medeba, Ch1 19:6, Ch1 19:7. David sends Joab to attack them; he defeats the Syrians and Ammonites, Ch1 19:8-15. The discomfited Syrians recruit their army, and invade David's territories beyond Jordan; he attacks them, kills Shophach their general, seven thousand charioteers, and forty thousand of their infantry, Ch1 19:16-18. The Syrians abandon the Ammonites and make a separate peace with David, Ch1 19:19.
Now it came to pass - See the same history, Sa2 10:1 (note), etc., and the notes there.
And cut off their garments in the midst - Usque ad eorum, pudenda. So the Targum, Jarchi, and others; leaving exposed what nature and decency require to be concealed. See on Sa2 10:4 (note).
Chariots and horsemen out of Mesopotamia - These are not mentioned in the parallel place in Samuel; probably they did not arrive till the Ammonites and their other allies were defeated by the Israelites in the first battle.
Thirty and two thousand - The whole number mentioned in Samuel is, Syrians, of Beth-rehob, and of Zoba, twenty thousand; of King Maacah, one thousand; of Ish-tob, twelve thousand; in all thirty-three thousand. Of chariots or cavalry there is no mention. These could not have been the whole army.
Be of good courage - See the note on Sa2 10:12.
Forty thousand footmen - See this number accounted for in the note on Sa2 10:18 (note).
They made peace with David, and became his servants - See on Sa2 10:19 (note), and the concluding note in that place; and see for omissions in Chronicles, the preface to these books.