"We can put it in the form of an illustration. The difference between an unbeliever sinning and a Christian sinning is the difference between a man transgressing one of the laws of England or any other State, and a member of a family doing something that is displeasing to another member of the family. In the one case a man commits an offence against the State; in the other a husband, say, has done something that he should not do in his relationship with his wife. He is not breaking a law, he is wounding the heart of his wife. That is the difference. It is no longer a legal matter, it is a matter of personal relationship now, and that, a relationship of love. The man does not cease to be the husband of the woman, nor the woman to be the wife of the husband. Law does not come into the matter at all; it lies outside that realm. In a sense it is now something much worse than a legal condemnation. I would rather offend against a law of the land objectively outside me, then hurt someone I love." Romans 7:1-8:4, Banner of Truth, page 278.
From the good doctor, D. Martyn Lloyd-Jones by way of Chris Brauns.