3 And I testify again to every man who becomes circumcised that he is a debtor to keep the whole law. 4 You have become estranged from Christ, you who attempt to be justified by law; you have fallen from grace. (Galatians 5:3–4, NKJV)
Binding any portion of the Old Testament Law of Moses upon Christians is totally incompatible with the gospel of Christ. The Law of Moses was only given to the nation of Israel; it was never a universal law given to all nations (Deut. 5:1-3). Paul was addresses a false doctrine being advanced by some Jewish Christians, which compelled Gentiles to be circumcised and keep the Law of Moses in order to be saved (Acts 15:1ff). This teaching perverted the gospel being preached by the apostles (Gal. 1:6-9). The result of believing and advancing this false doctrine was that Christians were severed from Christ; they were “fallen from grace.” This clear statement by the apostle Paul shows that it is possible for Christians to lose their salvation. This happens, not because Christ does not have the power to save the Christian, but because the Christian chooses to believe and follow error instead of truth. Sin will not be rewarded with heaven. The belief that Christians cannot fall away and be lost is a false, deceptive doctrine.