We have learned that the law cannot save. In fact, when man is given the law, we break the law even more. It shows the depravity of man. When we see how dark the human heart is, and how much it is condemned, we can then see how gracious our God who sent his Son to pay for our sins. Paul speaks of freedom here. The gospel brings us freedom. Freedom of the flesh, in particular. Paul presents a picture of a slave, and he uses it as an illustration of how a believer is different from one who is not.