Commentaries
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.
28. encamp against the city, and take it—It has always been characteristic of Oriental despots to monopolize military honors; and as the ancient world knew nothing of the modern refinement of kings gaining victories by their generals, so Joab sent for David to command the final assault in person. A large force was levied for the purpose. David without much difficulty captured the royal city and obtained possession of its immense wealth.
lest I take the city, and it be called after my name—The circumstance of a city receiving a new name after some great person, as Alexandria, Constantinople, Hyderabad, is of frequent occurrence in the ancient and modern history of the East.