And he smote Moab,.... He next went against that, and invaded it, the people of it being always troublesome and distressing to the children of Israel; and though the king of it had shown some favour to David, yet it was when he considered him as an enemy to Saul, and Saul to him; but things having taken a different turn, his and his people's enmity against David and his people appeared; wherefore he went and fought them, and made them his subjects, whereby was fulfilled the prophecy of Balaam, Nu 24:17; as it referred to David:and measured them with a line: either their country and fields, to distribute among his people, or rather the soldiers he took prisoners; which, as Procopius Gazaeus says, were so numerous that they could not be told, and therefore they were ordered to lie prostrate on the ground, and they were measured with a line, as it follows:casting them down to the ground; or ordering them to lie down; though some understand this of casting down their cities, towers, and strong holds, and levelling them with the ground:even with two lines measured he; with one, so it may be supplied, as the Vulgate Latin,to put to death, and with one full line, to keep alive; that is, in measuring them with his lines, he divided them into two parts, one he put to death, and the other, the full line, which contained the most, he saved alive; though it seems according to our version, and so most understand it, that David slew two thirds, and saved one, and so Josephus .
This must be understood of the army of the Moabites that fell into his hands, so Josephus, who persisted and refused to submit, not of all the inhabitants of the land. The Jews say , that the reason of this severe treatment of them was because they slew the father, and mother and brethren of David, whom he left to the care and custody of the king of Moab, when he fled from Saul, see 1Sa 22:3; since after that they are heard no more of; though it should rather be imputed to their enmity against the people of Israel.
The phrase of "meting out the valley of Succoth" seems to be an allusion to this fact, Ps 60:6, the psalm being written on occasion of the victories here related:and [so] the Moabites became David's servants; the inhabitants of the land who were left in it, perhaps that part of the soldiers preserved alive were brought home captives:[and] brought gifts; paid a yearly tribute to King David, as they afterwards did to Solomon and to Rehoboam, until the revolt of the ten tribes, and then they paid it unto the kings of Israel, to the times of Ahab, see 2Ki 3:4, though these gifts may be distinct from, and besides the tribute paid, which is supposed in their being servants, see 2Ch 17:11.
Thus the Arabians carried gifts to the king of Persia besides tribute. Antiqu. l. 7. c. 5. sect. 1. Bemidbar Rabba, l. 14. fol. 212. 1. Herodot. Thalia, sive, l. 3. c.