Galatians: Audience
We find out in Acts that while Paul and Barnabas were evangelizing this region, they were preaching the gospel by first going to the synagogues. When they met continued resistance from the Jewish leaders, they turned to the Gentiles who probably represented the majority of their converts. After their departure it seems as though some Jewish Christians followed them and were instructing these new believers on the necessity of obeying the Jewish law. In addition, these Jewish zealots were attempting to convince the Galatians of Paul's inferiority to the earlier apostles. It is most likely that these Jewish "Christians" were undermining Paul in order to give weight to their own purpose.
Knowing that these new Galatian converts were mere babes in Christ, Paul wrote passionately about his own dismay over what he considered their abandonment of the gospel. Paul came to them preaching a gospel of freedom in Christ, but they had allowed themselves to be enslaved to the law, denying the marvelous grace of God. They needed to reclaim their freedom in Christ as heirs of his promise, to be corrected in their misunderstanding of the importance and use of the law, and to be equipped for living as the body of Christ.