It is he that giveth salvation unto kings - Margin, "Victory." The Hebrew word means "salvation," but it is used here in the sense of deliverance or rescue. Even "kings," with all their armies, have no hope but in God. They seem to be the most powerful of men, but they are, like all other people, wholly dependent on him for deliverance from danger. David thus recognizes his own entire dependence. Though a king in the divine purpose and in fact, yet he had no power but as derived from God; he had no hope of deliverance but in him. It is implied further that God might as readily be supposed to be willing to interpose in behalf of kings as of other people when their cause was right, and when they looked to him for aid. See the notes at Psalm 33:16 : "there is no king saved by the multitude of an host." Compare Psalm 44:5-6.
Who delivereth David his servant from the hurtful sword - Who has done it; who can do it again; on whom alone David is dependent as all other men are. David speaks of himself by name elsewhere. See Psalm 18:50; 2-Samuel 7:26. He refers to himself also under the name of "the king," Psalm 61:6; Psalm 63:11. Caesar, in his writings, often speaks of himself in the same way.

He that giveth salvation unto kings - Monarchy, in the principle, is from God: it is that form of government which, in the course of the Divine providence, has principally prevailed; and that which, on the whole, has been most beneficial to mankind. God, therefore, has it under his peculiar protection. It is by him that kings reign; and by his special providence they are protected.

[It is he] that giveth salvation unto kings: who delivereth David his (i) servant from the hurtful sword.
(i) Though wicked kings are called God's servants, as was Cyrus in (Isaiah 45:1), for he uses them to execute his judgments: yet David because of God's promise and they who rule godly are properly so called, because they do not serve their own affections, but set forth God's glory.

It is he that giveth salvation to kings,.... Which is the reason of singing the new song to the Lord, or this is the matter of it. The Lord is the Preserver of men and beasts, the Saviour of all men, and especially of them that believe; who are in a spiritual sense kings and priests unto God; and in a temporal sense he saves high and low, rich and poor: but there is a particular providence respecting kings; who, as they are the powers ordained of God, and are his vicegerents on earth, and represent him, so they are preserved by him; were they not, there would soon be an end to all public order and government: they cannot save themselves; nor are they saved by their bodyguards about them; nor is any king saved by the multitude of his host, but by the Lord, Psalm 33:16. Or, "he that giveth victory to kings"; over their enemies; which is not obtained by the strength and force of their armies, and by their military skill valour; but by the right hand and arm of the Lord: and therefore, whenever this is the case, a new song should be sung to him; see Psalm 98:1. David no doubt has regard to himself, and to the many salvations God had wrought for him, and the victories he had given him; as also to the King Messiah, whom God heard and helped, as man and Mediator, in the day of salvation, and gave it to him, and in which he rejoiced, Isaiah 49:8;
who delivereth David his servant from the hurtful sword; David literally, the servant of the Lord by creation, redemption, and grace, as well as by his office, as king of Israel; him the Lord delivered from the sword of Goliath, as the Targum; from the sword of Saul, as Jarchi and Kimchi; and from the sword of strange children, as Arama; of all his enemies he had been or was engaged with in war: and David mystically, Christ the son of David, God's righteous servant, he chose, called, upheld; and in whom he was glorified, by doing his work diligently, faithfully, and completely; him he delivered from the sword of justice, when he had satisfied it; and from wicked men, like a sword; and from all his enemies, and death itself, when he raised him from the dead, and gave him glory; see Psalm 22:20. Aben Ezra thinks there is a defect of the copulative "and": and that it should be read, "from the sword and evil"; every evil person or thing; and observes, that some take it for an adjective, and understand it of an evil camp or company.