After Paul's successful evangelism work in
Galatia, the church of had suffered the problem of
Judaizers preaching that Christians were still bound to some
Old Testament laws and practices, among others,
circumcision and certain dietary restrictions. Judaizers argued that Paul was not a "real" apostle, claiming that in order to sugar-coat the gospel, he had removed legal
requirements. Paul replies by reassuring his apostolic authority, and explains how legal requirements perverts the Gospel. This is where the fundamental of Christianity, sola fide is introduced.
It is in this book that the essential doctrine of justification by faith in Christ alone is best explained. See verse 2:16, "...a man is not justified by observing the law, but by faith in Jesus Christ. So we, too, have put our faith in Christ Jesus
so that we may be justified by faith in Christ and not by observing the law, because by observing the law no one will be justified."
- Zondervan NIV Study Bible, p. 1780-81. (C) 1984 by International Bible Society