(4) For ever and ever.--This is merely a term for indefinite length. (Comp. the common salutation of a king: 1Kings 1:31; Nehemiah 2:3; Daniel 3:9.) An allusion to the eternal kingdom of the Messiah is not to be forced on the passage.

Verse 4. - He asked life of thee, and thou gavest it him, even length of days for ever and ever. The "life" intended cannot be ordinary human life, since in David' s case this certainly did not continue "for ever and ever." We must understand the psalmist to have asked for continuance in his posterity, and this was guaranteed him in the message which God sent him by Nathan (2 Samuel 7:13, 16). In the full sense the promise was, of course, Messianic, being fulfilled only in Christ, the God-Man, who alone of David' s posterity "liveth for ever."

21:1-6 Happy the people whose king makes God's strength his confidence, and God's salvation his joy; who is pleased with all the advancements of God kingdom, and trusts God to support him in all he does for the service of it. All our blessings are blessings of goodness, and are owing, not to any merit of ours, but only to God's goodness. But when God's blessings come sooner, and prove richer than we imagine; when they are given before we prayed for them, before we were ready for them, nay, when we feared the contrary; then it may be truly said that he prevented, or went before us, with them. Nothing indeed prevented, or went before Christ, but to mankind never was any favour more preventing than our redemption by Christ. Thou hast made him to be a universal, everlasting blessing to the world, in whom the families of the earth are, and shall be blessed; and so thou hast made him exceeding glad with the countenance thou hast given to his undertaking, and to him in the prosecution of it. The Spirit of prophecy rises from what related to the king, to that which is peculiar to Christ; none other is blessed for ever, much less a blessing for ever.He asked life of thee, and thou gavest it him,.... Both for himself, as man, when he was about to die, that he might be raised to life again, which was granted him; and for his people, that they might live spiritually and eternally, and accordingly life is given to him for them; and he has power to give it to as many as the Father has given him, John 17:2;

even length of days for ever and ever; the life he has for himself as man is what will ever continue; he will die no more, death will have no more dominion over him; he will live for evermore, and that to make intercession for his members, Romans 6:9; and the life which is granted them at his request is an everlasting one, both as to body and soul; for though they die as other men, they shall live again in the resurrection of the just, and never die more, but shall be like the angels in heaven; and as for the second death, that shall not harm them, nor have any power over them; they will live and reign with Christ for ever.