As we open the book of Galatians, Paul is talking about his Jewishness and the irony of his becoming a follower of Christ. Both of these things are going to become relevant as we read through this book. The Galatian churches were probably a mix of Jewish Christians (who had been the first focus of early missionaries, being the people of the promise) and Gentiles who were trying to worship with them. This created a bit of a problem, because the Christian faith was started by a Jew (Jesus!) but needed to include practices that didn't exclude those outside Judaism.