I will make an everlasting covenant with you, even the sure mercies of David.
The prophet has made reference to the promise made to David in the seventh chapter of second Samuel. In the preceding verses
of the chapter, Isaiah most tenderly entreats and invites the whole world to receive the promises of salvation, for thereby shall the poor, the wretched and the afflicted obtain the great treasures of joy and salvation. Immediately following the verse quoted, he speaks of the Messiah, the promised seed of David, as given to the Levites for a "witness,"—a preacher sent by God—and for a "leader and commander to the people." The thought is of a king and ruler differing from Moses and his priests and exponents of the law; a ruler differing from every other lord and king, from David and all worldly rulers ever, subjecting everything to himself.
Not that this leader should set up a new temporal government, or extend Jewish authority among the Gentiles, but that Jews and Gentiles should receive him and believe in him, and obtain the fulfillment of that promise he here terms a covenant of the sure mercies of David. This covenant God enters into and keeps, a divine, sure covenant; through Christ shall be given whatever blessings God's mercy shall bestow, with remission of sins, redemption from death, and life eternal.
Now, if the Christ of this covenant is true man, and, as the promise to David is, of David's flesh and blood; and if he is to bring eternal mercy, he must likewise be God, such gift being in the province and power of God alone. This being true,
he cannot remain in death, although he may suffer death by reason of his human nature; he must of his own power rise from the dead. Only so can he raise others and give them everlasting life; only so can he truly be called eternal King of grace, righteousness and life, according to the sure promise of God. Whenever the Scriptures speak of Christ's eternal kingdom, and of everlasting grace, they point out this article of the resurrection of Christ. God has promised to give us Christ, him who was to sit at his right hand—that is, to have the omnipotent, divine power possible only to an eternal Lord and King—and at the same time to have his kingdom on earth.