Therefore what will we say? The law is sin? May it never come to be! But I would not have known sin except through law. For indeed the covetousness I would not have known except the law says, “You will not covet.”
The Mosaic Law is righteous and logical, but it is not a means by which we are made righteous. Through the Law, we learn about sin—not how to be righteous. However, we would not have known sin unless it was revealed through the Law. Covetousness is the craving for what belongs to another person, and it is manifested in an action intended to take pleasure in what your neighbor has (Exodus 20:17).
Since in Christ we have died to the Law, this does not make the Law sinful. Rather, through the Law, we come to know sin; but through Christ—being freed from the Law—we learn to overcome sin through grace.