So David gathered all the people together and went to Rabbah and fought against it and took it.
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
And he took their king's crown from off his head,.... The crown of Hanun the king of the Ammonites, who now fell into his hands, and whom he stripped of his ensigns of royalty, who had so shamefully abused his ambassadors, Sa2 10:4, (the weight whereof was a talent of gold with the precious stones): or, "and a precious stone"; there might be more, as...
2Sa 12:29 Accordingly David “gathered together all the people,” - i.e., all the men of war who had remained behind in the land; from which we may see that Joab’s besieging army had been considerably weakened during the long siege, and at the capture of the water-city, - “and fought against the acropolis, and took it.”