In the past week I have seen where three separate people from the Reformed world that have all said that the Mosaic Covenant was exclusively a covenant of grace. I believe that they are wrong about that, and it appears based on some confused views that come from a more contemporary Reformed tradition influenced by people like John Murray, Norman Shepherd, and by others like John Piper. The theologians coming from that side of the issue have historically had problems with the covenant of works, or with tying Christ’s righteousness under the law to anything Adam was supposed to fulfill, and that can lead to some confusion and even mixing of law and gospel categories. I believe this confused view is now held by many in the Reformed world, and I wanted to at least get my own insignificant two cents in on this issue and see if I could perhaps put a finer point on what I think the Westminster divines were actually saying, and if it’s really accurate to say that the Mosaic Covenant was a covenant of grace.
My position is that it is s a mistake to simply call the Mosaic Covenant a covenant of grace, because God’s rescue of Israel seems to be part of the Abrahamic covenant, which was a covenant of grace. God remembered his promise to Abraham. The moral law presented in the Mosaic covenant can be said to be a servant of that covenant in that it taught Israel by leading them to Christ, but the law is not of faith (Gal 3:12).
When looking at the Mosaic covenant, it is also important to distinguish between the entire nation of Israel, and the individual Israelite.
The land and the law were a return to a type of Eden. “Do this and you will live” is a promise of eternal life if a faithful Israelite obeys the law perfectly the way Adam was supposed to. No one could, so it was a curse. At a national level, failure to obey received the sanction of ejection from the land. This is a picture of ejection from the garden and dwelling with God. The land was where man was to dwell with God in peace. It was a picture of or type of heaven.
For the individual the Westminster Confession of Faith does point to some aspects of the Mosaic Covenant and calls them part of the covenant of grace.(WCF 7.5) Particularly the sacrificial system, but they do not say that the Mosaic covenant itself is part of the covenant of grace. They say “during the time of the law” that the covenant of grace was delivered “administratively” via promises, prophecies, sacrifices, circumcision, the paschal lamb, and other types and ordinances that forsignafied Christ to come. Not all of that was in the time of Moses. For instance, King David lived in the time of the law, and there were promises made to his lineage. There were also prophecies made by Isaiah hundreds of years after the Mosaic covenant. Also, circumcision was given to Abraham 400 years before Moses. Generally, what they were speaking about is in the time of the old Testament, and we should note that the Mosaic covenant is not the sum of the old testament.
Just as in the garden, which was a covenant of works for Adam, we see the gospel promise of a seed of the woman (Gen 3:15) and we see God fashion coverings for them after they sin (Gen 3:21). So, we could say that “in the time of the Garden” the covenant of grace was delivered in that promise and in that sacrifice and covering, but we don’t call Adams’ time in the garden a covenant of grace. So we should reject any ham-handed approach that looks at WCF 7.5 and concludes that they were saying that the Mosaic Covenant was a covenant of grace.
However, since to the individual, the Mosaic covenant includes the law as a tutor serving the covenant of grace, and therefore parts of it that administratively deliver the covenant of grace, we could say it is a mixed covenant. It held forth the promise of life for perfect obedience under the law (COW), but it also offered up a substitute in the sacrificial system (COG) where the Israelites were also fully justified by Christ, though He had not come into the world yet to fulfill all righteousness under the law and be the lamb of God.
Since it is such a picture and return to that garden environment, it understood to the individual Israelite as a republication/restatement/post-lapsarian offering of of the covenant of works, but one that they could not fulfill, it was not presented to be their hope, but their hope was in the promises of God to Abraham and that they belonged to God who had first called them His people before presenting them with the law. From the perspective of the covenant of redemption it is an an environment for one to be the second Adam to enter and fulfill all righteousness in. It therefore required an unobtainable perfect obedience to the law that drove them to look to sacrificial substitutes that brought them grace in Christ.
The whole of Israel, the land, and the law should also be seen as that required post fall environment for Christ to be that second federal head who passes the probation earning the way back to the tree of life, and fellowship with God for the elect. Christ overcame Satan, not in the plush confines of Eden, but in the harsh wilderness of promise land (the second fallen Eden environment). So in that way for Christ it was covenant of works to keep. It was not grace to Him, it was by works of the law that He was to earn a perfect record of righteousness to impute to the elect.
On a national level the Mosaic covenant is explicitly about ejection from the land, but on the individual level, there was a call to “do this and you will live”. That is if by works, you love God with all your heart, and your neighbor as yourself, you will live. This was speaking ultimately of eschatological life, and though the promise was to all Adam’s offspring, only one who was fully God and fully man could have done it, and He did do it and was raised again from the dead vindicating His record of perfect righteousness. In that regard the Mosaic covenant is substantively a post-lapsarian type of the covenant of works.
It is substantively a covenant of works to Christ because as Christ said it was all about him (John 5:39). It was all about the promised seed of the woman. Born of a woman, born under the law to redeem those under the law (Gal 4:4-5). Christ earned heaven by His works in order to save us by grace alone through faith alone. Christ fulfilled the covenant of works to save us (and the Israelite who looked to the substitute, to Messiah) in the covenant of grace. So, for the individual Israelite, substantively, he was offered Christ dressed in His gospel. Yet for Christ it was not by grace. There was a works principle to fulfill, a probation to keep, eternal life to earn.