In the book of Galatians, Paul defends both his apostleship and the message of the gospel against those who were seeking to bring the believers in Galatia back under the bondage of the law.   Our justification is by faith in Jesus Christ, and not by any works of the law.  His exhortation is that the Galatian believers were to rest in the simplicity and liberty of faith in Christ, and that they learn to abound in the fruits of the Spirit.