26 And Joab fighteth against Rabbah of the Bene-Ammon, and captureth the royal city, 27 and Joab sendeth messengers unto David, and saith, 'I have fought against Rabbah—also I have captured the city of waters; 28 and now, gather the rest of the people, and encamp against the city, and capture it, lest I capture the city, and my name hath been called upon it.' 29 And David gathereth all the people, and goeth to Rabbah, and fighteth against it, and captureth it; 30 and he taketh the crown of their king from off his head, and its weight 'is' a talent of gold, and precious stones, and it is on the head of David; and the spoil of the city he hath brought out, very much;
Matthew Henry's Commentary on 2 Samuel 12:26-30
Commentary on 2 Samuel 12:26-31
(Read 2 Samuel 12:26-31)
To be thus severe in putting the children of Ammon to slavery was a sign that David's heart was not yet made soft by repentance, at the time when this took place. We shall be most compassionate, kind, and forgiving to others, when we most feel our need of the Lord's forgiving love, and taste the sweetness of it in our own souls.