It is often seen in Scripture how Law is against Faith, and that works of the Law cannot justify a person like Faith can. Since being like Jesus is the obvious wish of God and the goal of every true believer, it is hard to believe that any true Christian has ever construed this freedom from the Old Law to mean freedom to sin.
25 Now that faith has come, we are no longer under a guardian. – Gal 3
Paul in Galatians 3 is calling the Law of Moses that came after Abraham a guardian or like a school master that served it’s purpose and was no longer necessary once Jesus came. A person who turns to following Jesus Christ from the Old Law of Moses would never conclude he or she can live less holy than someone who lived by the ten commandments. Paul makes this point in Romans 6 saying things like “the wages of sin is death” and “things of which you are now ashamed” and “present yourselves to God as instruments of righteousness“.
The reason this issue deserves to be addressed is that some people have from the time of the Gospel clung to the Law and have clung to the idea of being good enough to have eternal life. And so they perpetuate a model of working to be righteous. They continue to emphasize the 10 Commandments and law keeping.
14 For sin shall not be your master, because you are not under law, but under grace. – Rom 6
In the Romans letter, Paul is addressing the problem of these who insist on intertwining the Gospel New Testament with the Old letter of the Law. Romans 7:1ff says it can’t be done and compares any attempts to as a type of adultery. He says that are damned for suggesting faith means freedom to sin.
8And why not say (just as we are slanderously reported and as some claim that we say), “Let’s do evil that good may come of it”? Their condemnation is deserved. – Rom 3.
And three chapters later in 6:1ff, Paul addresses the slanderous claim again by asking “Are we to continue in sin that grace might increase?” Rom 6:1.
And when Paul says in Romans 6:14 you are not under law, but under grace, he is addressing the error head on. Not that it means you now have a free path to sinning, but that by faith in Christ is the only way to be truly made sinless by God.
The way the Law adherents choose to combat the Apostle is by suggesting that Paul was establishing a license to sin by his telling sinners they are not under Law. See, Christians were under no illusion that grace and freedom meant a free for all to sin. That was just the lie being put forward to slander Paul and prejudice others not to turn from Judaism and the Old Law.
These of the Judaism persuasion hated it that people were convinced they could be justified by faith. Paul talks about these people in Galatians 2, saying, “4it was a concern because of the false brothers secretly brought in, who had sneaked in to spy on our freedom which we have in Christ Jesus, in order to enslave us.” Gal. 2. The “false brothers” are the ones who were trying to steer Christianity back into something under the umbrella of the Mosaic Law. They are the type who would slander Paul saying he was telling people they could sin all the more under grace.
Peter and Paul and others made it clear that being justified by faith is the only way to be holy in God’s sight. But faith gives freedom, but not freedom to do evil. In 1 Peter we see this reminder to not believe the slanderous lie that you can intentionally go about sinning and be pleasing to God.
16 Act as free men, and do not use your freedom as a covering for evil, but [use it] as bondslaves of God. – 1 Pt 2. And, 13 For you were called to freedom, brethren; only [do] not [turn] your freedom into an opportunity for the flesh, but through love serve one another. – Gal 5.
So here is the conclusion: those who are free in Christ are to live holy lives by faith. The Law of Moses with all of its commandments were given by God to be replaced by the Law of Christ, Gal 3 and Rom 7. James calls the new the Perfect Law, the Law of Liberty, Jas 2:25. With the New Testament of Christ, the Old Law/Testament faded away because while it was “holy, righteous and good”, it served it’s purpose. Now that faith has come, and justification by faith, we do not attempt to rebuild the Old Law system, see Gal 2:18-19. Instead, Christians love Jesus and seek to be like Him in all of their behavior.