This was a question from the Theology forum that I did not want to sidetrack.
I'm a bit confused as to where you stand regarding the Sinai Covenant and the New Covenant.
There are other things I'm probably confused about regarding Messianic Judaism but if you could give me a quick explanation of how you regard those two covenants I would appreciate it.
First off let me preface this by saying that what I present here is not representative of ALL Messianic Judaism.(MJ) Indeed, Judaism has THRIVED on differences of opinion since at least the first century bc when Rabbis Hillel and Shammai disagreed on over 100 points of doctrne and practice, started competing schools to train Pharisees, and yet remained best friends and each insisted his pupils marry a daughter of a graduate of the other
school. Their disputes and differences (along with that of later rabbis) are recorded for us in the Mishnah and Talmuds.
That said, with a growing body of young MJ theologians and rabbis like David J Rudolph (son of my own rabbi Mike Rudolph) these positions are gaining traction across the scope of MJ. David has built on the theological works of Dan Juster ThD and his father.
I should add in here a brief note about the Jewish approach to scripture. It varies from the normal Christain approach in that it is not as technical, academic or abstract. Indeed Judaism tends to reject abstractions in favor of relational truths and the approach to doctrine reflects that. So does the Jewish system of logic.
Now to your question.
First we must look at what a "covenant" actually is. (this is from the work of R. Mike Rudolph) As he was a lawyer (licenced in Maryland, Virginia and DC) before coming to faith, he was well versed in the legalities of covenants. After coming to faith he also studied the historical mid east covenants.
A covenant is this, no more and no less: A binding agreement. It can be written down or verbal. It can be formal or informal. But it is BINDING. In the ancient mid east it was binding to life and death.
According to Dr Derek Prince (i knew him personally and he was a friend of Rabbi Dan Juster) God relates to man ONLY thru a covenant.
There have been many biblical covenants between God and man over the years: Adamic, Noahic, Abrahamic, Mosaic, Davidic and the New Covenant. Those are the major ones. there are also minor ones like the "covenant of peace" given to Phineas, Aaron's grandson.
Both the Mosaic and New covenants are based on the Abrahamic covenant.
MJ is not a dual-covenant system as some would think. It is clearly a NEW Covenant Judaism. So WHY do Messianic Jews insist on following Mosaic regulations?
Covenants can have attached documents that were not part of the original agreement but have force. A king can have a covenant with his vassals and attach certain conditions and remunerations that can vary with different circumstances. It is easier to ammend a "rider" document than the original covenant. If for some reason the covenant itself has to be renewed or re-established, that rider can continue as is or be thrown out or amended and then attached to the new covenant.
We messianics see the bulk of the Mosaic code of 613 commands as being that "rider" that carried over into the New Covenant. Clearly some parts are no longer relevant like the animal sacrifices. Most are for Israel only.
The New Covenant follows this same pattern. The covenant is Our Lord dying and raising to life again, his blood shed for sins and our agreeing to His Lordship. "All who call upon the name of the LORD shall be saved." Then Paul and Peter and James etc come along and supply the additional rider documents with instructions on how best to fulfil our part of the covenant. They are binding (required) but they are not the Covenant itself.
Having a rider like that that is NOT part of the actual covenant allows for differing requirements for various subgroups within the covenantal membership. For a secular example - the covenant may demand a tax on all farms. The rider says it is to be 100 bushels of wheat. But if you live in an area that grows figs or grapes or olives? The requirement can be adjusted to that environment.
So we see it for Jewish followers of Jesus and Gentile followers of Jesus. Per the first Jerusalem council of Acts 15, Gentiles were exempted from the continued observance of the Mosaic rider, the 613 commands. A list was started of 4 commands. Paul expanded it from there. But the understanding was (and is borne out inActs 21) that Jews should continue to observe as much of the Mosaic rider (not the covenant proper) as is proper in a New Covenant environment. Some of those commands are related to specific callings on the Jewish people and according to Romans 11, those callings are ongoing - "irrevocable." It includes being the keeper of God's word (Rom 3) and being a light to the world. There are more beyond that.
Matt 23 (end of the chapter) in the "Messiah's Lament" Our Lord says He will not be seen by Jerusalem (where Zechariah says He will return) until they - Jerusalem - The Jewish people = say "blessed is He who comes in the Name of the Lord," which is the part of the Jewish wedding ceremony where the bride welcomes the comming of her groom.
So we see maintaining the customs and lifestyle of Judaism (which was built around keeping the 613 commands) as important. We also see Gentile Christianity as important and equal to what we have and are. But we do not see trying to bind any of those 613 as required by gentiles. Indeed Gentiles have their own list of commands to keep (some overlap with the 613) which has about 1000 NT commands.
I am out of time for now. Any questions?