Paul’s augmented rebuke of Peter says: if you’re going to live by the law at all, you have to live by it in total. But to do so would be pointless, since even we Jews know that we are not justified before God by that law, but by faith, specifically the faith of Jesus. So there is no place, the implied argument goes, for tiers within Christ’s followers based on adherence to Jewish customs.
In Paul’s understanding of the gospel, compromise on circumcision would not simply have been about unity. Rather it would have undercut the integrity of the entire gospel and of Christ’s work on the cross.
Galatians 2:3-10 (3) But not even Titus, who was with me, though he was a Greek, was not compelled to be circumcised (4) because of false brothers smuggled in (who slipped in to spy out our freedom which we have in Christ Jesus in order to enslave us), (5) to whom we did not yield…
After years of proclaiming the Gospel, Paul finally goes to Jerusalem to present his message to the original followers of Jesus, not because he has any doubts himself but because he feels compelled to do so by the Holy Spirit.
In the second half of Galatians 1 Paul asserts the God-givenness of his Gospel. The bare Gospel that Paul preaches is from God and therefore needs no further refinement or augmentation by humans. This is God’s good news first and foremost.
If we want to be plain spoken and unconcerned with pleasing men in the Pauline sense, what that means for us is that we should be bold in proclaiming the good news that Jesus has died for our sins and has been raised from the dead for our salvation.