Paul wrote this letter to the Galatians to warn them of how they were changing their belief of the gospel. They were subtly starting to believe that they must finish in the flesh what was begun in the Spirit. They had forgotten the simplicity of the gospel. The Galatian church had been infected with "another gospel." The Letter to the Galatians is the Apostle Paul's antidote. They had been led to believe that what was begun in the Spirit was to be perfected through the flesh. They had been led astray. Paul's correction is two-fold: the completeness of salvation through the sacrifice of Jesus, the Christ, and the source of sanctification a life in the Spirit. Jesus died to pay the price for sin, crucified that flesh on the cross, and gave them His Spirit to live within them and live through them. Just as Moses could not get the children of Israel to the Promised Land, so the law and the flesh can not either. The law is Perfect and Complete, and is the school Master that only leads them to Jesus, whose Righteousness and Holiness fulfilled the law, and leads His children to the Promised Land. (peppersnoodles93 and by smolderinsmithy)