One is hard pressed today to find a short, and yet, careful and thorough explanation about the place and function of the Mosaic Covenant in the Covenant of Grace in redemptive history. The more that seems to be written on it, the more confusion ensues. It is for this reason that I was again delighted--as I work through Geerhardus Vos' Reformed Dogmatics--to  find, what I believe to be, one of the most satisfying answers to what is quite possibly the most hotly debated aspect of Covenant Theology in the Reformed church today. As he continued to work through some of the more theologically difficult aspects of Covenant Theology, Vos opened up questions about the relationship of the Mosaic Covenant to the Abrahamic Covenant, questions about the Mosaic Covenant and the Covenant of Works (i.e. the republication issue), as well as whether the Sinaitic Covenant was one, two or three different covenants--among other things. In Questions 43-47, he explained: 43. How is the covenant at Sinai to be assessed? On this question, the most diverse opinions are prevalent. We first give the correct view. The Sinaitic covenant is not a new covenant as concerns the essence of the matter, but the old covenant of grace established with Abraham in somewhat changed form. The thesis that it must be a new covenant is usually derived from the fact that Paul so strongly accents the law over against the promises as different from them (e.g., Gal 3:17ff.). But thereby one thing is forgotten. Paul nowhere sets the Sinaitic covenant in its entirety over against the Abrahamic covenant, but always the law insofar as it came to function in the Sinaitic covenant. There is only one place that appears to be an exception to this: Gal 4:21ff. Here, in fact, two covenants are set over against each other. But they are not the Abrahamic and the Sinaitic covenants. Rather, they are the earthly and the heavenly covenants—the covenant that originates from Mount Sinai and has its center in the earthly Jerusalem, and the covenant that originates from heaven and is concentrated in the Jerusalem that is above. This is very significant. Paul has not said: two covenants, the one originating from Mamre and the other from Sinai. He knew well that already with Abraham something of the Sinaitic side of the covenant was also present and that, conversely, after Sinai there was a continuation of the heavenly, spiritual side of the covenant of grace with the people of God. So with this passage, one gains nothing. The children of Israel were in the covenant when they set out from Egypt. Precisely because they were in it, they were delivered from Egypt (Gen 15:13–14). There is not one word mentioned of a new relationship. The old was altered. And at the same time, there was something new. It consisted in the following considerations: a)   Now, for the first time, the covenant with Israel rightly became a national covenant. The social life of Israel, its civil organization, its existence as a people, were brought directly into contact with the covenant of grace. These two were inextricably linked. One cannot say, “I want to leave the Jewish church but remain in the Jewish state.” Whoever left the church left the state. And one could leave the state only by being exterminated from the people. Properly speaking, there is discipline through censure in a certain sense, but not, properly speaking, discipline only through excommunication or cutting off from the church. The sanction was the death penalty. All this first came about at Sinai. Earlier, God Himself had cut off Ishmael and Esau from the covenant administration. Judicially, this is later no longer permitted. b)   The covenant with Israel served in an emphatic manner to recall the strict demands of the covenant of works. To that end, the law of the Ten Commandments was presented so emphatically and engraved deeply in stone. This law was not, as Cocceius meant, simply a form for the covenant of grace. It truly contained the content of the covenant of works. But—and one should certainly note this—it contains this content as made serviceable for a particular period of the covenant of grace. It therefore says, for example, “I am the Lord your God.” Therefore, it also contains expressions that had reference specifically to Israel, and thus are not totally applicable to us (e.g., “that it may be well with you in the land that the Lord your God gives you”). But also, beyond the Decalogue, there is reference to the law as a demand of the covenant of works (e.g., Lev 18:5; Deut 27:26; 2 Cor 3:7, 9). It is for this reason that in the last cited passage, Paul calls the ministry of Moses a ministry of condemnation. This simply shows how the demand of the law comes more to the fore in this dispensation of the covenant of grace. This ministry of the law had a twofold purpose: 1) It is a disciplinarian until Christ. 2) It serves to multiply sin, that is, both to lure sin out from its hidden inner recesses as well as to bring it to consciousness (cf. Gal 3:19; Rom 4:15; 5:13). Paul teaches expressly that the law did not appear here as an independent covenant of works in Gal 3:19ff. That the law is also not a summary of the covenant of grace appears from the absence of the demand of faith and of the doctrine of the atonement. c)   The covenant with Israel had a ceremonial and a typical ministry, fixed in its details. That was also already so in part for the earlier administration of the covenant of grace. But to the degree that it now came about, that ceremonial ministry was something new. A formal gospel preaching was offered continually by symbols and types. A priestly class came into existence. Earlier, every father of a family was a priest. Now, particular persons are separated and consecrated for this function. One must consider all these types and symbols from two points of view: 1) as demands of God on the people; 2) as a proclamation of God to the people. God had appointed them to serve in both respects. But the Jews overlooked the latter aspect more and more, and made the types and symbols exclusively serve the former purpose. That is to say, they used them only as additions to a self-willed covenant of works, and misunderstood the ministering significance they had for the covenant of grace. So the opinion arose that righteousness had to be obtained by keeping that law in the broadest sense of the word, including the ceremonial law. And by this misuse, the covenant of grace of Sinai was in fact made into a Hagarite covenant, a covenant giving birth to servitude, as Paul describes it in Gal 4:24. There he has in view not the covenant as it should be, but as it could easily become through misuse. d)   The law given by God also served as a rule of life for Israel. So, we obtain a threefold law: the moral, the ceremonial, the civil law. This civil law was a particular application of the principles of the moral law. For example, in the moral law God says in general, “You shall not steal.” The civil law further elaborates what constitutes stealing, what penalties apply, etc., etc. At the same time, this law as a rule of life for civil concerns was elaborated in such a way that it provided a model for the spiritual relationship to God of the members of the covenant. Israel must bring its tithes, firstfruits, drink- and vow-offerings; and in doing that the dedication of the covenant member to God was also foreshadowed in the covenant of grace. No one from Israel may be a slave, for every Israelite is as such already totally God’s possession. Even the land of the children of Israel is God’s property; they are merely sojourners and aliens toward God, who live from what is His. So, too, in civil relationships in Israel, in the civil side of the covenant, the essence of the covenant of grace is mirrored. 44. Is this covenant that God established with Israel capable of being broken or not? It is not only capable of being broken, but also has been broken repeatedly. Then a covenant renewal is necessary, as comes out in Exod 34:10ff. and 2 Kgs 23:3. Actually, all sin is covenant breaking, but still this covenant is such that God Himself has ordained a means to preserve the covenant in spite of those sins. This means are the sacrifices. They are applicable to sins that are not committed with uplifted hands; that is, sins through error, unintentional sins. But, also, even when an intentional sin is committed, God still does not forsake His covenant. Where the appointed means of propitiation is lacking, God comes with extraordinary seeking grace, remembers His covenant, maintains it in spite of Israel’s unfaithfulness (Exod 32; Psa 106:23; Num 16:45–50). Finally, it is expressed clearly that the covenant with Israel is eternal (1 Chr 16:17; Isa 54:10; Psa 89:1–5), a covenant to which God has pledged the honor of His name (Isa 48:8–11; Num 14:16). In this pledge, therefore, it is essentially settled that God guarantees the continuation of the covenant of grace, that it is eternal in a different sense than the covenant of works, that however much individuals may fall away and be lost, the core of the covenant remains and must remain—so, entirely the same thing we established earlier about the covenant of grace in general. 45. How can it be said in Deut 5:2 and 3 that God did not make the covenant at Horeb with the fathers, if it is still one covenant? This must be understood not of the substance, but of the form of the covenant closure. With Abraham and the patriarchs, God had not established the covenant of grace in its Sinaitic design—that is what Moses means here. Thus by “the fathers” is meant the patriarchs, not the forefathers in Egypt (Calvin), or those who perished in the wilderness (Augustine). It is clear from subsequent places how Scripture regards the Sinaitic covenant as a continuation of the covenant with Abraham: Exod 2:24, “And God remembered His covenant with Abraham, Isaac, and Jacob”; Lev 26:42, “Then I will remember my covenant with Jacob, with Isaac, with Abraham” (Deut 4:31; 2 Kgs 13:23). Again and again, there is a continual pointing back to the covenant with Abraham to show that the children of Israel were in that covenant. 46. What are the deviating positions regarding that Sinaitic covenant of grace? a)   The view of Cocceius and his followers. Cocceius was a proponent of a trichotomy, that is, a three part division of administering the covenant of grace. There was:

1. An administration from Adam to Moses.
2. An administration from Moses to Christ.
3. An administration after Christ.

Or, expressed otherwise: ante legem—sub lege—post legem, that is: before the law, under the law, after the law. The last period unfolds in seven stages that correspond to the seven letters, seven trumpets, seven seals of Revelation. Regarding the establishing of the covenant at Sinai, Cocceius taught that the Decalogue was a summary of the covenant of grace, made especially applicable to Israel. However, after the establishment of this gracious covenant upon the ten words, when Israel became unfaithful and fell into worship of the golden calf and broke the covenant, then as punishment the legal covenant of ceremonial institutions was established, that is, the covenant of grace as a much more rigorous and harsher administration. The servitude of the law first appears after the worship of the golden calf. And the element of servitude is found in the ceremonial law; that of grace, on the other hand, in the law of the Ten Commandments. The fathers who lived before Sinai were under freedom, under promise. According to the Cocceian understanding, the Old Testament first begins at Sinai. God did not give a law to the patriarchs. Cocceius taught of the pre-Mosaic sacrifices that they were not commanded by God but were free ceremonies that could be neglected without guilt. The Cocceian view of the Sabbath was also related to this judgment about the pre-Mosaic freedom, and the Decalogue as a temporary formulation before the covenant of grace. It was thought that the Sabbath was not mandatory. b)   A second conception does better justice to the legal nature of the Ten Commandments. They are regarded as a form of a new covenant of works that God established with Israel. God did not establish it with the intent that by it Israel could earn life, for through sin that had become completely impossible. The aim was to allow them to attempt it in their own strength. In Egypt, they had lost the awareness of their impotence. This awareness had to be revived, and the new covenant of works served that end. “They were puffed up as it were with an absurd confidence in themselves and said, ‘All that the Lord has said we will do.’ ” God then gives them the law. But when they saw the terrifying display of the smoking and burning mountain, of the dark cloud and the lightning, they soon perceived that they could not live by this covenant of works and therefore asked for Moses to be their mediator. In connection with the consciousness of guilt awakened in this way, God renewed with Israel the Abrahamic covenant of grace, as recorded in Exod 24, to which the Levitical laws also belonged. “The Book of the Covenant” was thus the summary of the covenant of grace, not the Decalogue engraved on stone tablets. In the ceremonial laws that were added later, the gospel element was resident. This is thus an opposite view from Cocceius and his school. c)   According to a third conception, at Sinai God established not two but even three covenants with Israel:

1. A national covenant.
2. A covenant of nature or of works.
3. A covenant of grace.

The first of these was made with all the Israelites, without exception, and was a continuation of the setting apart of one nation, the extension of the particular line that begins with Abraham. In this covenant, God promised Israel temporal blessings, and required in turn civic, external obedience. The prophets lament the violation of this national covenant through idolatry. The second covenant was a repetition of the covenant of works and was established by the proclamation of the Decalogue. The promise of life and the threatening of death were solemnly uttered anew. The third covenant was the renewing of the covenant of grace established with Abraham and was sealed through the announcement of the ceremonial law (thus Maestricht, VIII, Chapter II). 47. What objections must be made against all these proposals? a)   That they are against the presentation of Scripture in multiplying the covenants. Never and nowhere is it presented as if more than one covenant was established at Sinai. b)   That they are in part wrong where they wish to limit the moral law or the ceremonial law entirely to one of these covenants. This cannot be achieved. We have already seen how, for example, the ceremonial law had a double aspect. These were demands that had to be fulfilled and that, through the impossibility of complete fulfillment, should drive people to Christ. At the same time, they were types and symbols that pointed to Christ and pictured Christ. Thus the ceremonial law of itself already appeared under the two covenants that one wishes to separate. It is likewise so with the moral law. In it occur features that recall the covenant of grace. It is not simply a law of the covenant of works. The promise of eternal life is not clearly expressed in it. And explanations that do present this promise occur in the midst of the ceremonial law.^{[1] [1]} Vos, G. (2013). Vol. 2: Reformed Dogmatics (R. B. Gaffin & R. de Witt, Ed.) (A. Godbehere, R. van Ijken, K. Batteau, D. van der Kraan & H. Boonstra, Trans.) (76–80). Bellingham, WA: Lexham Press.