I think john2 is right:
there was more than that according to:I think the issue in Antioch between Paul and Peter was about keeping table fellowship with Gentiles rather than circumcision.
Compelling the Gentiles to live like Jews does not mean they have to be circumcised, just having them to become God-fearers, that is living like a Jew with all the traditions.
rgprice wrote:However, Paul does go on to say that, "before certain men came from James, he used to eat with the Gentiles. But when they arrived, he began to draw back and separate himself, for fear of those in the circumcision group. The other Jews joined him in his hypocrisy, so that by their hypocrisy even Barnabas was led astray."
But in his reference to "those in the circumcision group," is Paul saying that they advocated for Gentile circumcision or is he only describing them as being Torah observant Jews? I'm thinking it is the latter.
In the big picture, I think Paul is angry because Peter and the other Jews were modeling a way of life that he considered to be no longer relevant for Jews, for which he was reproved by those sent from James and (in my view) by James in his letter (and which I think could be the reason Paul says he was willing to pretend to be Torah observant around Jews in 1 Cor. 9:20). I think he calls them "those in the circumcision group" because they were Torah observant and not because they advocated for Gentile circumcision.
This is most likely part of an interpolation (2:7-8, except "to the contrary"). See https://depts.drew.edu/jhc/Barnikol.html"they saw that I had been entrusted with the gospel for the uncircumcised, just as Peter had been entrusted with the gospel for the circumcised"
My take, and with some evidence: Peter was providing his testimony to Jews about Jesus' public life and the Jerusalem church after Jesus' death (with anecdotes). He was telling about message of Jesus: you have to be poor & righteous (Jew) to get in the kingdom of God when it comes (very soon!).
The church of Jerusalem softened the message a bit: You have to live like a poor. And the best place to do that is to join the church of Jerusalem (after paying a fat entrance fee!).
See http://historical-jesus.info/28.html and http://historical-jesus.info/20.html and http://historical-jesus.info/109.html