Myers turns to the Davidic covenant in his tenth chapter. Once again, he is seeking to demonstrate that the biblical covenants stand in continuity with one another as administrations of a unified covenant of grace.
Myers notes several links between the Davidic and the Mosaic covenants First, though no Israelite kings had been anointed yet, Deuteronomy 17 laid down the law for Israel’s kings. Second, the Davidic covenant required faithfulness to the Mosaic law (1 Kings 2:3-4).
Myers also argues that the Davidic covenant establishes an “office of covenant mediator” for the covenant of grace.
Myers notes again the dynamic of promise and obedience within the covenants. In the Davidic covenant “the obedience of the Davidic king is necessary and important,” but “God’s faithfulness will not be affected by the obedience or disobedience of that mediator” (236). Thus, disobedience brings discipline, but the promises made to David will be fulfilled.
The Davidic covenant poses a problem for Myers because of the exile. In his words, “the exile can appear to be the strongest argument for rejecting the suggestion that there is one, eternal covenant of grace, for in that exile God seems to take away the embodiment of His promises only to begin afresh later with Jesus Christ” (237). Myers resolves this problem by appealing to Vos’s dual-level typology. Since the earthly type refers not only to a “future fulfillment” but also to an “eternal, heavenly reality” it does not matter “if the line running from the earthly type to ultimate fulfillment seems to disappear” since “the line from earthly type to heavenly reality remains” (238).
Myers ends by showing how Christ’s mediatorial kingship is rooted in the Davidic covenant.
I agree with Myers about the links between the Mosaic and Davidic covenants, but I think this shows the two covenants to be part of a unified plan of redemption rather than evidence that they are part of the same covenant of grace. One reason for not seeing the two as part of the same covenant is that the Mosaic covenant is clearly a conditional covenant (the covenant curses come upon those who break the covenant and the covenant blessings are forfeited) whereas the Davidic covenant is unconditional. As Myers notes, though disobedience brings chastening for individual disobedient kings, the covenant blessings of the Davidic covenant will infallibly be brought about.
I confess that I don’t see the exile as a major threat to a unified covenant of grace. Nor do I see Vos’s dual level typology helpful here. The mediatorial kingship of Christ is not a “eternal, heavenly reality.” It is an incarnational reality, which means that it is temporal and earthly.