The enemy shall not exact upon him. Here it is declared in express terms, that although David may not be without enemies, the power of God will be always ready to maintain and defend him, that he may not be oppressed with unrighteous violence. It is accordingly affirmed, that David will not be tributary to his enemies, as he who is vanquished in battle is constrained to grant such conditions of peace as his conqueror may dictate, however injurious to himself these may be. When his enemies are called sons of iniquity, it is tacitly intimated, that this government will be so exempt from tyranny and extortion, that whoever shall attempt to overthrow it will be involved in the perpetration of wrong and wickedness. The amount is, that David and his successors will be so secure and strongly fortified by the divine protection, that it will be impossible for their enemies to treat them as they would wish. In regard to the fact, that God suffered this kingdom to be greatly afflicted, so that David's successors were constrained to pay a vast amount of tribute to foreign and heathen kings, it is not at variance with this promise; for, although the power of the kingdom was reduced, it was enough that the root still remained, until Christ came, in whose hand the kingdom was at length firmly established. As both the king and the people wickedly rejected this singular blessing of God, the kingdom was often shaken through their own default, afterwards impaired, and finally ruined. Yet God, to confirm his oracle concerning the perpetuity of this kingdom, ceased not all along to cherish and preserve some hope, by contending against their ingratitude. Besides, when mention is made of David's haters and oppressors, it is intimated, that this throne will not be privileged with exemption from annoyances and troubles, inasmuch as there will be always some who will rise up in hostility against it, unless God set himself in opposition to them.

The enemy shall not exact upon him - The literal meaning here is derived from the force sometimes used in extorting or demanding a debt, where no indulgence is shown, but where it is exacted to the last mite, whether the man is able to pay it or not. Compare Matthew 18:25, Matthew 18:28. Then it is used to denote oppression, or subjugation, which is the idea here. The enemy shall not be suffered to act the part of one who rigidly exacts the payment of a debt; that is, he shall not be allowed to oppress him.
Nor the son of wickedness afflict him - This is copied almost literally from 2-Samuel 7:10. The phrase "the son of wickedness" means simply the wicked. He shall not fall into the hands, or under the power of wicked men.

The enemy shall not exact upon him - None of his enemies shall be able to prevail against him. It is worthy of remark that David was never overthrown; he finally conquered every foe that rose up against him. Saul's persecution, Absalom's revolt, Sheba's conspiracy, and the struggle made by the partisans of the house of Saul after his death, only tended to call forth David's skill, courage, and prowess, and to seat him more firmly on his throne. The Philistines, the Ammonites, the Syrians, etc., united all their forces to crush him, but in vain: "God beat down all his foes before his face," and variously plagued those who opposed him, Psalm 89:23.

The enemy shall not exact upon him,.... The enemy is the devil, as in the interpretation of the parable of the tares, Matthew 13:39, the implacable enemy of Christ and his church; and yet, notwithstanding all his enmity and malice, he could not "exact", or get more inflicted on him, than the law and justice of God required of him, as the sinner's surety; or could not "exact" a tribute of him, or make him tributary to him; or, in other words, conquer him, and subject him to him: so far from it, that he was conquered by Christ, and all his principalities and powers spoiled; or could not "deceive" him, in which sense the word (b) is sometimes used; and so the Targum here: though he deceived Eve, he could not deceive the Messiah, the seed of the woman; he tried it, in person, by his temptations in the wilderness, and by his agents and instruments, the Scribes and Pharisees: but in vain, and to no purpose; he could not succeed:
nor the son of wickedness afflict him: at least not always: he was indeed afflicted, as by wicked men, and by Satan the wicked one, yet not so as to be overcome by any; and as Christ personal, so Christ mystical, or his church and people, are afflicted by the sons of wickedness; yet, sooner or later, they are delivered out of all their afflictions. Antichrist, that man of sin, and son of perdition, that wicked one, that is eminently so, and may be well called "the son of wickedness", has long and greatly oppressed the people of Christ, and his interest; but he shall not always; he shall be destroyed with the spirit of his mouth, and with the brightness of his coming, 2-Thessalonians 2:3. This passage is applied to the Messiah by the Jews (c).
(b) "non imponet ei", Tigurine version; "non seducet eum", so some in Vatablus; "non decipiet eum", Gejerus, Schmidt. (c) Yalkut Simeoni, par. 2. fol. 56. 3.

by restraining and conquering his enemies, and performing My gracious purpose of extending his dominion--

Exact - Not conquer him or make him tributary.