Then Joab sent messengers to David to say, “I have fought against Rabbah and have captured the water supply of the city.
We have here an account of the conquest of Rabbah, and other cities of the Ammonites. Though this comes in here after the birth of David's child, yet it is most probable that it was effected a good while before, and soon after the death of Uriah, perhaps during the days of Bath-sheba's mourning for him. Observe, 1.
Commenting on 2 Samuel 12:26-31
Now therefore gather the rest of the people together,.... The rest of the soldiers in the land of Israel, and come to Rabbah: and encamp against the city; invest it in form: and take it; upon a surrender or by storm; for it could not hold out long: lest I take the city, and it be called after my name; so great a regard had...
the city of waters--Rabbah, like Aroer, was divided into two parts--one the lower town, insulated by the winding course of the Jabbok, which flowed almost round it, and the upper and stronger town, called the royal city. "The first was taken by Joab, but the honor of capturing so strongly a fortified place as the other was an honor reserved for the king himself."