Galatians
Paul had led the Galatians to Christ. They had made a good start in the Christian life and were doing well spiritually. Later, some Jewish teachers (called Judaizers) taught the Galatians that to be saved one must not only believe in Christ, but must also obey the Mosaic Law, the sign of which is circumcision. In preaching this heresy, they also attacked Paul's apostleship and gospel. Their false teachings begin to hinder the Galatian's obedience to the LORD GOD, and they were starting to observe some parts of the law, as well as considering a complete acceptance of the law.
Paul writes his epistle to expose the error of the Judaizers' gospel and their impure motives. His ultimate goal is to prevent the readers from embracing a false gospel and to encourage them to retain their spiritual freedom in Christ. Paul's focus is the justification by God's grace through faith, the true message of salvation received directly from Jesus Christ.