Here's a few thoughts on the occasion and purpose for the writing of Galatians. Who were the opponents of Paul in Galatia? What was the nature of the opponents’ doctrine and how did Paul respond to it?
The book of Galatians reveals people to have been composed mainly of converts from heathenism (4:8), but partly also of Jewish converts, who probably, under the influence of Judaizing teachers, sought to incorporate the rites of Judaism with Christianity, and by their active zeal had succeeded in inducing the majority of the churches to adopt their views (1:6; 3:1). This epistle was written for the purpose of counteracting this Judaizing tendency, and of recalling the Galatians to the simplicity of the gospel.
The epistle was probably written very soon after Paul's second visit to Galatia (Acts 18:23). The references of the epistle appear to agree with this conclusion. The visit to Jerusalem, mentioned in Gal. 2:1-10, was identical with that of Acts 15, and it is spoken of as a thing of the past, and consequently the epistle was written subsequently to the council of Jerusalem. The similarity between this epistle and that to the Romans has led to the conclusion that they were both written at the same time, namely, in the winter of A.D. 57-8, during Paul's stay in Corinth (Acts 20:2, 3).
Paul’s answers the great question discussed is, Was the Jewish law binding on Christians? The epistle is designed to prove against the Jews that men are justified by faith without the works of the law of Moses. After an introductory address (Gal. 1:1-10) the apostle discusses the subjects which had occasioned the epistle. Paul continues to communicate the purpose for his writing in that salvation only comes through faith in Christ and not on any meritorious act, morality, ethnic background, etc. Paul continually points to the fact that salvation is a free gift given to man.
Conservative scholars have historically assumed Paul’s opponents were Judaizers and have interpreted the text in that light. Paul's opponents were Jew-ish Christians who sought to "Judaize" the Gentile Christians of Galatia. The Judaizers' identity best satisfies the "mirror-reading" criteria and limitations, Barclay concludes that the troublers were probably Jewish Christians who also questioned the adequacy of both Paul's apostolic credentials and the gospel he preached.
Paul always responded in a bold way but showed his love to the people through his writings. Paul always responded and showed people they were wrong, he did not back down. Paul clears up the importance of the change of the heart and how all of the customs and many laws that the Judaizers were adding to salvation, he helps them know that true salvation only comes through faith in Christ.