In the following, I have summarized the basic points of my argument in a series of theses.
Thesis: The unique legal aspects of the Mosaic covenant are dependent in their very nature on the nature of the Mosaic covenant as a redemptive covenant of grace.
Thesis: The unique legal aspects of the covenant of grace are interwoven with the ceremonial and judicial laws.
Thesis: The ceremonial and judicial laws are dependent on the Mosaic covenant as a covenant of grace.
Thesis: For instance, the sacraments of the Mosaic covenant are signs and seals of the grace of Christ to come when received by faith. Thus the ceremonial law administers the grace of Christ to come.
Thesis: Since the unique legal aspects of the Mosaic covenant administer Christ's grace, the Mosaic covenant must be the eternal covenant of grace legally administered.
Thesis: The legal aspect of the Mosaic covenant administered blessings and curses to the people of God, but true old covenant saints only experienced these curses in terms of the external aspects of the covenant.
Thesis: This situation is the flip side of Hebrews 6:4-6, in which hypocrites externally participate in the external blessings of the covenant. Hypocrites only experience these blessings externally as borrowed capital from the elect and their justification. But hypocrites are themselves neither justified nor truly sanctified. This situation existed in the old covenant too, as suggested in Hebrews 6:4-6. However, the old covenant also expressed the flip side of this situation. In the old covenant, saints were truly justified and truly inwardly sanctified, but they could be externally cursed in relation to the visible earthly arena of Canaan. In this sense, they experienced the old covenant curses.
Thesis: These old covenant curses, as the saints experienced them externally, separated them from the historical arrival of the kingdom of heaven that would come with Christ. When Christ came as high priest, he took these external covenant curses away from his people and brought the historical arrival of the kingdom of heaven.
Thesis: Since the salvation of all saints throughout redemptive history is an intrusion of the eschatological kingdom to come, the same work of Christ was the ground for the arrival of the kingdom of heaven and its intrusion in previous redemptive history.
Thesis: Hebrews reveals that the ceremonial law was essential to the unique legal administration of the Mosaic covenant.
Thesis: According to Hebrews 8:8, the old covenant was a failure because God found fault with the people.
Thesis: This fault and its reversal reveal two things to which we must do justice in our formulation of the Mosaic covenant. It reveals that the unique legal aspects of the Mosaic covenant were grounded in the grace of the Mosaic covenant. It also reveals that the Mosaic covenant was uniquely legally administered in a way that the new covenant is not.
Thesis: When God found fault with the people, he was finding fault with the Aaronic priestly ministry. This ministry was integral with the ceremonial law which administered the eternal grace of Christ to come. Therefore, God found fault with the way his own grace was administered through actions of the priesthood.
Thesis: Though this fault is parallel, it is synthetically related to the fault God will find with those who reject the new covenant. Hebrews 8 suggests that the fault of Israel functioned in a unique legal fashion not found in the new covenant. For the writer (in conjunction with Jeremiah) suggests that this fault resulted in curses upon the saints of the old covenant (in some respect), while the curses of the new covenant only fall on those who despise the new covenant. The writer also suggests this when he implies that this fault resulted in something that the historical arrival of the new covenant will reverse forever. During the new covenant, it is impossible for the fault of the covenant people to result in precisely the same consequences in all respects.
Thesis: Hebrews 8:8 in context shows that the fault God found with Israel was integrally tied to the fault of the priesthood. Verse 8 begins with "for" (the second word in Greek), showing that it is dependent on the argument of the previous verse. Verse 7 also begins with "for," bringing us back to verse 6. Hebrews 8:6 says, "now he has obtained a more excellent ministry by as much as he is also the mediator of a better covenant, which has been enacted on better promises." Here the writer presupposes the inadequacy of the Aaronic priestly mediators of God's grace. God finds fault with them.
Thesis: This is not only part of the context in Hebrews; it is also part of the context in Jeremiah 31:31, which Hebrews 8 quotes. Jeremiah 32:31-32 teaches that God will execute the curses of the covenant upon Israel and Judah for the sins of their kings and priests as well as the sins of the people. Here the fault of the people is interwoven with the fault of the kings and priests. It is likely that Jeremiah is not simply referring to the kings and priests as individuals, but highlighting their failures in respect to their official duties. This would seem to be confirmed by Jeremiah 33:14-22. There the eschatological age will fulfill the promises made to David, bringing an eschatological king and priesthood (vv. 17-18). This eschatological service is presumably the reversal of the sin of the kings and priests in the Old Testament in terms of their official capacities. Therefore, Hebrews is contrasting a priesthood, which administered God's grace according to the old covenant order, to the priesthood of Christ who brings the eschatological kingdom of grace.
Thesis: The Mosaic covenant had a unique legal aspect (which we have shown was dependent on its nature as the eternal covenant of grace.)
Thesis: This is seen in the contrast between Hebrews 8:8 and 8:10-12. Because of the people's fault, God will put his laws upon their hearts and forgive their sins in a new way that he did not do in the old covenant.
Thesis: In the new covenant, God forgives the sins of his people in a new way, by not inflicting them with the external curses of the Mosaic covenant. By removing these curses and fulfilling eternal righteousness, Christ brings the eternal kingdom of God in history.
Thesis: That the new covenant reverses the eternal aspect of the covenant curses is found in the context of Jeremiah's prophecy. There we find that the new covenant will reverse this situation: "the father's have eaten sour grapes and the children's teeth are set on edge" (31:29). By contrast, in the new covenant "every man will die for his own iniquity." This latter statement interprets the former. In the old covenant, sons were dying for their father's sins.
Thesis: But how can this be, since the law of God forbids the killing of sons for their father's sins? We suggest it is connected with God's own execution of his covenant curses on the nation of Israel. Since the nation often suffered these curses as a whole, one person might die for the sins of his countrymen or his fathers before him. Those seeking an example of this may look to 2 Kings 21, where, as a result of Manasseh's sin, God promises to unleash his covenant curses on Judah in spite of the reforms of Josiah. That is, despite the righteousness of any of Israel's sons that follow, they will be judged for the sins of their fathers in the Babylonian Captivity. This is seen in the deportation of Daniel and perhaps Jeremiah's own exile. They are cut off from the land of life and inheritance. They receive the covenant curses. And perhaps some of the righteous are even killed by the sword.
Jeremiah is suggesting that the new covenant will reverse the situation of the theocratic curses. This is one aspect of what Jeremiah means by his prophesy. God set his face against his people and unleashed his covenant curses upon them. Now he will forgive their sins forever (even to the extent of removing these external covenant curses from them, Jer. 31:34, Heb. 8: 12). Doing so, he will bring the historical arrival of the kingdom of heaven, administered by the new covenant.
Thesis: In Hebrews, the kingdom of heaven is otherwise described as the eternal inheritance. Therefore, the blood of Christ brings the eschatological inheritance (Heb. 9:15). In exile, God's covenant curses separated righteous Israel from her inheritance in the land. It separated them externally from something that was considered their inheritance in God.
Thesis: Since the removal of these curses brought the eternal inheritance historically, we may conclude that these external curses also held back the arrival of the kingdom of heaven. Only when God removed these curses did he bring the historical arrival of the eternal inheritance.
Thesis: The sacrifices of the law were not able to remove the covenant curses which separated God's people from the historical arrival of the kingdom. This is one aspect of what the writer means when he says that the blood of bulls and goats could not take away sins (Heb. 10:4). That is, they could not bring the age of perfection (10:1), which Christ brought (10:14). Instead, the sacrifices were a constant reminder of sins (10:3). This reminder is connected with God's covenant curses, for this reminder is reversed when God does not remember his sins against his people (10:17)—the writer once again quoting this new covenant promise.
Thesis: If this is the case, then the sacrificial system partially looked toward the removal of these covenant curses. And in some cases, it was the means by which God alleviated these curses, by cleansing the unclean, and bringing them back into a fuller participation of the covenant blessings. A careful study of Leviticus would reveal these connections, and further strengthen the claim that the ceremonial law was an instrumental means of externally alleviating the covenant curses and bringing external covenant blessings. Thereby, the legal aspect of the Mosaic covenant with its blessings in contrast to curses was ultimately dependent on the administration of the covenant of grace through the ceremonial law.
Thesis: However, this entire process was not able to mediate the eschatological forgiveness of sins which brings the historical arrival of the eschatological inheritance. The ground of semi-eschatological forgiveness (Christ) must dispense it directly.
Thesis: The removal of the external curses of the covenant was only one aspect of the coming sacrifice of Christ. This work was also the ground of eternal salvation for all those who lived at any point in redemptive history. For all salvation is an intrusion of the eschatological kingdom. Therefore, the ground of both must be the same—i.e., Christ himself.
Thesis: When Hebrews connects the eschatological priesthood of Christ to better promises (8:6), it is speaking about the fact that Christ's priesthood brings the historical arrival of the eternal inheritance. The writer is thinking eschatologically.
Thesis: Hebrews is not denying that the Aaronic priesthood administered the eternal grace of God through types and shadows. As we have noted, the eternal salvation of all the saints throughout redemptive history was a foretaste of the eschatological age. This is true even though the grace of the semi-eschatological age possesses greater fullness than that foretaste. So nothing forbids the Aaronic priesthood from administering that foretaste, even though it does not bring and administer the greater grace of the new covenant. That is the point of the greater promises described in Hebrews. The Aaronic priesthood did not bring the semi-eschatological age. But this does not deny that they administered a foretaste of that coming age.
Thesis: In fact, Hebrews itself suggests that the old covenant was an administration of the eternal grace of God. This is seen when Hebrews teaches that there is a synthetic relationship between old and new covenants.
Thesis: This synthetic relationship is found in the connection of the judgment meted out in the old and new covenants.
Thesis: Hebrews 10:28-29 states: "Anyone who has set aside the Law of Moses dies without mercy on the testimony of two or three witnesses. How much severer punishment do you think he will deserve who has trampled under foot the Son of God and has regarded as unclean the blood of the covenant by which he was sanctified, and has insulted the Spirit of grace?" This formula is similar to those found in Hebrews 2:2-3, 9:13-14, and 12:25. Hebrews 2:2, 10:28-29, and 12:25 suggest that the new covenant brings to fullness the eschatological judgments intruded through the Mosaic covenant. This suggests a real synthetic relationship of judgment. Real eschatological judgment intruded is now real eschatological judgment fully unleashed in the final judgment.
Thesis: This suggests that a similar synthetic relationship of grace lies behind the contrast between the old and new sacrifices in 9:13-14. This further implies that the real grace of God was administered through those sacrifices, though they also had relation to the legal aspect of the Mosaic covenant to cleanse the flesh.
Thesis: Hebrews 10:28-29 states that those who reject the new covenant are despising the sacrifice of the covenant of grace. The author's argument is dependent on the synthetic relationship between the old and new covenants. Therefore, the argument assumes that those judged by the old covenant despised the blood of that covenant. This synthetic argument is best maintained if the blood of that older covenant also administered the eternal grace of God.
Thesis: That the old covenant curses arose from rejecting the grace of God is revealed in Romans 6:4-6. Here the writer speaks of the new covenant people of God by drawing a synthetic relationship between them and the people of Israel who came through the exodus. The exodus generation experienced the heavenly light, tasted of the manna in the wilderness and the miraculous power of God in delivering his people. These were God's works of redemptive grace and his means of offering them eternal life. Therefore by rejecting these things, they were cursed forever.
Thesis: Those in the church who despise the new covenant despise the blood of Christ (Hebrews 6:6). In this instance, Hebrews 6:6 is parallel to 10:28-29. Both suggest that in the old covenant, apostasy involved despising the blood of the covenant. The synthetic argument of this section is best maintained when the blood of both covenants administers the eternal grace of God.
Thesis: If the blood of the old covenant does not administer the eternal grace of God, there is no reason to believe that the curses for rejecting it were an intrusion of the eternal wrath of God. But Hebrews 2:2, 10:28-29, and 12:25 taken together clearly imply that the curses of the old covenant were an intrusion of the eternal wrath of God for rejecting the old covenant and its blood.
Thesis: This synthetic relationship between the old and new covenants implies that the old covenant punishments were a judicial intrusion of new covenant curses. That is, they are an intrusion of the judgment that falls upon those who despise the new covenant. If the Mosaic covenant administered an intrusion of wrath for rejecting the new covenant of grace, then the Mosaic covenant must itself have been a covenant of grace.
Thesis: Further, Geerhardus Vos has forcefully argued that the old covenant tabernacle was an intrusion of the real heavenly tabernacle that would come in fullness in the new covenant (Heb. 8:5). If the old tabernacle was an intrusion of the future reality, it certainly administered that reality through its sacrifices.
Thesis: The old tabernacle (which administered this reality) is an institution of the Mosaic covenant. Therefore, the Mosaic covenant administered the reality of the grace of Christ before the time.
Thesis: And again, finally, if the Mosaic ceremonial law was not an administration of the covenant of grace, then its sacraments were not sacraments of the covenant of grace. And Israel had no true heavenly communion with God through them.
Thesis: The writer of Hebrews compares the old covenant (in its legal relation) to the present cosmos. And so, as he draws us to the new covenant, he calls us to the heavenly city, to see how the glory of God and our inheritance in him surpasses all the glory of this world.
Thesis: This new covenant inheritance is the fullness of rest in God that was offered to the saints of old. God called them to open up their hearts to him, so turning aside their hearts from the world. So in the new covenant, God has transformed our hearts in Christ by his eschatological work and glory, cleansing our hearts with pure water, and calling us to see by faith how much more glorious Christ is than the present cosmos.
Thesis: In this call to worship, Christ is the great high priest of his people. He brings the eschatological age. That age is embodied in himself, as the priest who worships the Father in the heavenly places. So in him, we are called to worship the Father, having come to an age of greater access in which we are not separated from the holy of holies by the old covenant curses. Instead, we have been bound to Christ in a bond of brotherhood, in which we worship in him, singing God's praises for his great and mighty work and his everlasting life. Our true inheritance and our everlasting reward is Christ Jesus.