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>> “James insists that Christians must keep the OC Law, but Peter and Paul disagree.” <<
That is a categorically false statement.
You may be confused about some passages, but all of the apostles preached Torah.
Paul, in Romans 2, is in perfect agreement with James epistle. John’s epistles also preach a strong pro Torah message.
Peter doesn’t specifically engage the question, but every mention of Peter demonstrates his adherence to Torah.
All of the Acts is a storyline of the apostles perfect keeping of Torah. The NT is full of mentions of Paul cutting trips and visits short to be able to get to Jerusalem to keep a feast.
What do you use for a Bible?
>>>That is a categorically false statement.<<<
I addressed this in post #389 and in a previous thread (On the Infallibility of Tradition, Scripture, Magisterium). The early Church was originally a sect of Judaism and kept the OC Law for about the first two decades until the council of Ac.15 where it was abandoned.
But I do not think you are addressing the discussion of this thread. It is about the validity of Roman Catholicism as the "one church". If your argument is that RCs should keep the Law, go tell that to the RCs. If you want to discuss all Christians keeping the Law, start a new thread.