I am still thinking about James, especially as he appears in Acts 21. While this might seem a bit afield from Acts and Pauline theology, I think that James is a bit of a window into why Paul’s gospel was so radical in the first century, especially his declaration that Gentiles are saved apart from the Law.
James seems to represent a Jewish Christianity which continues to keep the Law in a way that fulfills Matthew 5:20. If one was to be a part of the kingdom of God, then one kept the whole Law. The idea that the people of God need to be absolutely Holy when the messiah comes is found at Qumran. The people who wrote the Dead Sea Scrolls seemed to have lived in a state of Temple Purity all of the time, a state which the priest who was serving in the Temple had to maintain. Even the Pharisees maintained a higher level of purity than was required by the Law, although this may not have been in anticipation of the kingdom.
It is possible that the emphasis on circumcision and food laws which were so troublesome in the Galatian churches is a result of the Second Temple period emphasis on Works of the Law, boundary markers which defined who was a Jew and who was not.
Using the book of Acts and the letter James wrote, we can see that James was associated with the most Jewish form of Christianity which remained based in Jerusalem. In Acts 15 James leads a church which includes Pharisees and priests (probably the same people, many priests were also Pharisees). Like Paul, these men came to understand that Jesus was the Messiah and that he would return soon to judge the world and Israel and establish the Kingdom of God in Jerusalem.
There was a broad range of views on the status of the Gentiles in the coming kingdom in the Second Temple period. For the most part, the gentiles would either be converted and included in that kingdom, or judged and excluded from that kingdom. Some Jews thought there would be more or less mass conversions, but on the other end of the extreme, few if any gentiles would be converted (and probably most Jews would be excluded!)
When Paul arrives in Jerusalem in Acts 21, the issue James raises has to do with Paul’s keeping of the Law. Some in Jerusalem think that Paul has left Judaism and no longer keeps the Law. So even at this late date, James represents a group in Jerusalem who are Christians, but are keeping the Law.
Was Law a requirement for salvation for the Jewish believers in Jesus? Probably not, although it is inconceivable to this group that there would be Jews who did not want to keep the Law. Keeping the Law is the only possible response to the grace which God has given – how could you not demonstrate your justification by doing the things which God requires? By way of analogy, there are many Baptist churches which would agree that baptism is not a requirement for salvation, but it is inconceivable that anyone who was truly a Christian would not get baptized. It is simply the natural thing to do, if you have become a Christian. So too the Law, if you were a Jewish believer, you simply did the Law because it was the proper response to God’s grace.
Back to Paul. I think that Paul would agree with James on Jewish use of the Law. Where he differed (radically) was that Gentiles did not convert to Judaism in order to be “right with God,” and therefore were not required to do the Law. James, on the other hand, likely though that Gentiles were in fact converting to Judaism, or at the very least ought to be under the sojourner laws while living in The Land (the point of Acts 15).