There are a few verses in the New Testament that tell us we “are not under the law” (Rom. 6:15; Gal. 5:18). Though some use this as permission to act however you want so long as you’ve confessed Jesus, most Christians realize that God’s commandments are still in effect. Jesus did not “come to destroy the Law or the Prophets … but to fulfill” (Matt. 5:17), and Paul said his own writings “establish the law” rather than repeal it (Rom. 3:31).
So why do these passages tell us we’re not under the law? I’ve heard many explanations, and touched on some myself, but none of them really answered the question of why Paul would use this phrase. They focused more on trying to say “that’s not really what he meant” than on trying to figure out why Paul chose these words to argue his point. Recently, though, I came across the best analysis of the phrase “not under the law” that I’ve ever seen. It was just a short passage in a little book called Fill These Hearts: God, Sex, and the Universal Longing by Catholic writer Christopher West.
Bondage to Sin
West writes about our desires — that we can either deny them and go on a “starvation diet,” indulge them in this life like “fast food,” or direct them toward God and partake in His “banquet gospel.” When addressing the idea of freedom in relation to desire, he says,
The Apostle Paul writes that those who “are led by the Spirit .. are not under the law” (Gal. 5:18). They’re free from the law — not free to break it (that’s license); they’re free to fulfill it because they don’t desire to break it. Christ didn’t come into this world to shove laws down our throats. He came into the world to align the desires of our hearts with the divine design so we would no longer need the laws (140)