Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. Matt 5:18
Let us look at the original NT Greek, which reads (approximately)
"ouranos kai ge para-erchomai" ("sky & land come-forth", literalistic translation).
Those four words, in that exact order, appear next in the Olivet Discourse, after Jesus deserted the temple of Jerusalem (
Matt 24:35),
"ouranos kai ge para-erchomai" but His Words will never pass away.
And, those words appear in the Apocalyptic Prophesies of
2 Peter 3:10 = Rev 21:1, when heaven & earth pass away, at the Coming of God, on the Great-White-Throne, to Judgement of earth (after the Millennium, and then also after the End Times, when Satan is loosed out of guard, to marshall Gog & Magog
vs. the Church).
So, seemingly unambiguously,
the Law & Prophets (Tanakh) remain, until Judgement.
i think that implies, that Jewish Christians would have to keep the Law, since the Law was Dispensed to them. But, gentile Christians are "grafted in" (Rom 11)
via the Jerusalem Council of 50 AD (Acts 15). God gave the OT to Jews, through whom He gave the NT to gentiles (approximately).
That "two-tiered" structure characterized the early Church,
e.g. James, the Bishop of Jerusalem, was famous for his Jewish-style piety, praying daily in the physical temple in Jerusalem, until he was martyred in 62 AD, by the High Priest Ananias, sacrificed about the time that the physical temple was finished, finally, after 80 years of renovations, and presumably then rededicated to the God of the Jews. (For nearly the next 8 years, a Prophet appeared in Jerusalem, named Jesus ben Ananias, who ceaselessly Prophesied the Doom of Jerusalem, with the words "woe, woe to Jerusalem", until the Romans sacked the city, in 70 AD.) James Tabor has been writing, recently, about Bishop James, "brother of the Lord" (Gal 1), and "pillar Apostle" (Gal 2); he may be overstating the role of James, who was head of the Church in Jerusalem,
i.e. Bishop there-of, but not necessarily head of the Church world-wide,
e.g. Peter was Apostle to the Jewish diaspora world-wide.