“For freedom Christ has set us free; stand firm therefore, and do not submit again to a yoke of slavery.” (Galatians 5:1)
Paul maintains that those who uphold the keeping Law as the means to salvation do not understand what they are getting themselves into. They are committed to keeping it perfectly which is impossible. The result is not freedom or unity with God, but only a harsh slavery. Keeping the Law makes no one more righteous or holy, just as none of our righteous deeds do. What it does do is bring us under the condemnation of the Law when we are supposed to be living lives of freedom in the Spirit.
But living in the Spirit does not give us license to indulge the flesh and engage in immorality as perhaps legalists might argue. They think believers need a written code, a set of rules and rites to guide them. Paul says you only need the Spirit. Those whom the Spirit indwells are not perfect but will, by the power of God, shun immorality in all its forms as well as all selfish behaviors. They will not only desire to live in righteousness, at peace with God and all men, but they will manifest the fruit of the Spirit in their lives. Thus true believers are not marked by physical markers, ethnicity, the deeds of the Law, or by following rituals, but by a host of righteous attitudes and qualities that show that they are not living for self but for God and their brethren. This fruit will be manifest in concrete actions not mere words.