The city of waters - The lower town of Rabbah (the modern Ammam), so called from a stream which rises within it and flows through it. The upper town with the citadel lay on a hill to the north of the stream, and was probably not tenable for any length of time after the supply of water was cut off.

And have taken the city of waters - The city where the tank or reservoir was that supplied the city and suburbs with water. Some think that the original, לכדתי את עיר המים lachadti eth ir hammayim, should be translated I have intercepted, or cut off, the waters of the city: and Houbigant translates the place, et aquas ab urbe jam derivavi; "And I have already drawn off the waters from the city." This perfectly agrees with the account in Josephus, who says των τε ὑδατων αυτους αποτεμνομενος, having cut off their waters, Antiq., lib. vii., cap. 7. This was the reason why David should come speedily, as the citadel, deprived of water, could not long hold out.

And Joab sent messengers to David,.... To acquaint him how he had proceeded, and what success he had had:

and said, I have fought against Rabbah; laid siege to it, and skirmished with parties that sallied out upon them:

and have taken the city of waters; the same with the royal city, and so the Targum here renders it; so called because situated by the waterside; Adrichomius says (x) the river Jabbok flowed round about it: or it abounded with fountains of water, from whence the other part of the city, or what was properly the city Rabbah, was supplied with water; and which communication being cut off, it could not hold out long, which Joab being sensible of, therefore sent for David. Junius and Tremellius render the words, "I have intercepted the water from the city"; with which the account of Josephus (y) agrees, who says, that he cut off the water from them, and precluded other supplies, so that they were in great distress for want of food and drink; and in like manner it was taken by Antiochus some hundreds of years later; for that; historian says (z) the siege by him lasted long, and they could not prevail, because of the multitude of men it, until one of the prisoners showed them a subterraneous passage, through which they came and fetched water; which they stopped up with stones and such like things, and then through want of water yielded.

(x) Theatrum T. S. p. 34. (y) Antiqu. l. 7. c. 7. sect. 5. (z) Polyb. Hist. l. 5. p. 414.

And Joab sent messengers to David, and said, I have fought against Rabbah, and have taken the city of {r} waters.

(r) That is, the chief city and where all the water pipes are, is as good as taken.

12:27 Of waters - Rabbah was so called because it was encompassed with water.

27. 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."

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.