Bible Notes Online - 1-Chronicles 19 - ESV
Commentary

v1-4: Although David had defeated many nations, he sought good relationships with some, see 14.1-2. David wanted to show kindness to Hanun the son of Nahash, king of the Ammonites. In his kindness and mercy, he became vulnerable to the deceptions of others. Such mercy depends on the giver, not the recipient.

The princes of Ammon convinced Hanun that David was planning to invade their land. Our acts of kindness may be misinterpreted. Those who habitually practice deception assume that others are being deceitful, see 2 Sam 22.26-27; Ps 18.25.

v5: Although David was provoked, he did not respond by military force. He showed his concern for his messengers who had been disgraced.

v6-7: Ammon feared that David would attack, so he hired extra troops. Their reaction shows how little they understood the heart of a spiritual man.

v8-13: David was concerned to defend his people. He sent Joab, commander of the army, to stop the invading army. Joab used sensible measures, in splitting his army to fight the two armies coming against him. He encouraged Abishai to "fight bravely for our people"; they had a responsibility to protect the people.

v14-18: A second attack was defeated decisively.

v19: Only after the two defeats did the Arameans make peace with David.