In the book of Galatians, Paul uses the concept of justification by grace through faith apart from the works of the Law to teach sanctification by grace through faith. This is especially true with chapter 5. Paul is really not talking about how to get saved here or about the possibility of losing salvation, but about what legalism does to one’s ability to grow, mature, and experience the power of God in his or her life. When one trusts in some form of legalism (as in circumcision or whatever) for righteousness before God whether for salvation or for sanctification, they have fallen out of the grace way of life by faith in the finished work and provision of Christ and they are depending on a system of works which is totally unable to produce spiritual change from the inside out. This renders the benefits of Christ’s life null and void for spiritual change and maturity. Note in the context that follows, Paul discusses the change and victory over sin by the power of the Spirit of God. Though I will insert a comment here or there, by-in-large, the following arguments regarding the meaning and theme of this passage can be found on our web site under Galatians.
A. Paul exhorts the Galatians to apply the gospel to their lives by standing firm in their freedom, not being separated from the benefits of Christ, and using their liberty for service rather than for sin 5:1—6:10
B. Paul exhorts the Galatians to stand in their freedom, and not to be separated form the benefits of Christ as the perverters of Grace were advocating. 5:1-12
1. Thesis: Since Christ set the Galatians free for the advantage of freedom, the Galatians should defend their freedom, and not subject themselves to slavery again (through seeking to keep the rules of the Law as with circumcision) 5:1
2. Sphere of Law: Paul warns the Galatians that if they move toward works of the Law (circumcision) in order to acquire righteousness or even sanctification righteousness before God, that they will separate themselves from the benefits of knowing Christ (e.g., lose the advantage of Christ for their spiritual growth, they will become a debtor to all of the Law, and they will be separated from the effective rule of Christ having gone astray from the rule of Christ) 5:2-4 This does not mean the loss of salvation, but that the benefits of their new life if Christ have been made ineffective because their faith in their own works of Law rather than in the sufficiency of Christ and Spirit of God (see Romans 8:1ff). (a) Paul affirms that if the Galatians receive circumcision that Christ will be of no advantage to them (in their spiritual growth and victory over sin) 5:2 Compare 5:16ff. (b) Paul affirms that everyone who receives circumcision is a debtor to keep all of the Law 5:3 (c) Paul affirms that those who are seeking to be righteous by the Law have been separated from the effective rule of Christ, they have gone astray from the principle of grace 5:4. To fall from grace means to fall from God’s provision for deliverance, growth, and victory into Law, a system dependent on man, not God.
3. Sphere of Grace: Paul explains that believers who continue in faith (meaning faith in the finished work and sufficiency of Christ) wait for the confident expectation of righteousness and increase in righteousness (spiritual growth) through their faith in Jesus and their love for others by the Spirit 5:5-6 (a) The reason why Paul has just described the negative effect on those returning to the Law is because in contrast to their position, those who are under the Spirit’s direction are awaiting not only their ultimate righteousness by faith, but the experience of righteousness in this life (sanctification) 5:5 Again, this is clear from the context as expressed in 5:16-25. (b) The reason why Paul has just described the negative effect on those returning to the Law is because righteousness does not come through keeping laws, or not keeping laws, but through faith (in what Jesus has done (this includes the ministry of the Spirit as described later in this chapter) which works through love (for others) 5:6
In the final analysis, then, Paul is not in the least suggesting that such a believer is no longer in Christ, but by legalism, they have rendered their new life ineffective for spiritual growth and change by the power of God. I am afraid this is true with thousands of Christians who have not only failed to comprehend their own weakness, but the sufficiency of Christ. In the process, by attempting to keep a set of taboos or legalistic rules, they are trying to be spiritual by their own strength.