We’ve seen that by early in the second century, many believers in Jesus, especially Gentiles, no longer considered their faith to be a branch of Judaism, as Paul had considered it. What would account for such a drastic change in perspective in so short a time?
One of the main causes of this about-face seems to be the Fiscus Judaicus, a tax that Rome imposed on Jews. Shortly after the destruction of Jerusalem in 70 C.E., Rome, under emperor Vespasian, enacted this tax, which amounted to two days wages per year for everyone between three and sixty years of age. For a family, this would have been the equivalent of thousands of dollars in our currency.
The important thing to consider is, “Who was a Jew?” The collectors of the tax had every incentive to collect the tax from as many as possible. It was purposely targeted toward those who lived Jewishly, even if they claimed not to be Jews.
Many believers in Jesus who were ethnically Jews would have seen no option but to pay the tax, since they would have been considered traitors to their people if they refused. The big issue is how Gentile believers would have responded. They had been living Jewishly, biblically, but they didn’t consider themselves Jews. The temptation would have been great to distance themselves from Judaism in order to save a lot of money.
It’s almost inevitable that under these circumstances the trend would be toward developing non-Jewish, even anti-Jewish traditions. They would need to leave the synagogues and find a justification for worshiping on a different day of the week than the biblical (Jewish) Sabbath. They would need to develop different holy days than the biblical festivals. They would even need to define their religion as something different from, even opposed to, Judaism.
All of these things occurred within a remarkably short span of time. Some of the writings of Paul were ambiguous enough that they could be taken as teaching against Torah obedience. These were embraced and made the core of anti-Torah theology.
One of the evidences for this quick change in lifestyles of Gentile believers was a letter written to the Emperor Trajan by Pliny the Younger, a provincial governor, about 110 C.E. This letter describes Christians without any references to Jews or Jewish practices. It’s clear that by this time they were considered a totally separate religion from Judaism.
There is a really helpful in-depth treatment of the Fiscus Judaicus and its effects. It is by Christopher O’Quin and it can be found at https://www.torahresource.com/EnglishArticles/Fiscus%20Judaicus.pdf .
It is really sad that so many believers in Jesus were willing to deny such a large part of their spiritual identity, and doom centuries of their descendents into doing the same. But economic pressures are powerful incentives.
It is up to each one of us to study the New Testament to determine what Jesus and the apostles taught, rather than relying on centuries of Christian tradition.