The Writer:
In Galatians 1:1 and again in Galatians 5:2 the Apostle Paul identifies himself as the writer of this book. Much of chapters one and two (Galatians 1:11-2:21) are an autobiography of his life.
The Recipients:
According to Galatians 1:2, the letter was written to "the churches of Galatia." If you look on a map of the Bible lands, you will find that Galatia is an area on the north side of the Mediterranean Sea close to the east end of the sea. This area, which is a part of present-day Turkey, was a province controlled by the Roman Empire. It was made up of several cities. Paul was not writing to a single city but rather to a group of churches located in several cities of the Roman province or region of Galatia.
The Occasion of the Writing:
Paul visited this area and preached in several cities during his first and second missionary journeys. You can read about his work in that area by reading Acts chapters 13 and 14 (his first missionary journey) and Acts 16:1-10 (part of his second missionary journey). His treatment in these cities ranged from attempting to stone him to death (Acts 14:4-6 and 19) to asserting that he was a god (Acts 14:11-13).
Main Thoughts of the book of Galatians:
The apostle spends little time with cordiality with the Galatians. He makes his point that they are "so quickly deserting" the one who had called them (Christ) and the gospel (Galatians 1:6). The way that they were deserting the gospel was that they were turning it into a gospel of works so as to earn salvation. Paul assures them that there is not another gospel (Galatians 1:7) and that those who try to tell you that there is are "accursed" (Galatians 1:8-9). Much of the book is spent explaining the difference between salvation by faith and salvation by works. Paul goes so far as to warn them that, "You are severed from Christ, you who would be justified by the law; you have fallen away from grace" (Galatians 5:4).
Another major theme of the book of Galatians is a defense of Paul's apostleship and authority. There were ones who did not accept that Paul was on the same level as other apostles. Paul defends himself by showing where he got his message, which is from God by revelation and not from man. In fact, he was so bold as to oppose Peter for false teachings and practice. Paul asserts that his apostleship is not at all inferior to that of the other apostles.