Therefore by the deeds of the law no flesh will be justified in His sight, for by the law is the knowledge of sin.
Our walk is in Christ and not the law. It is good to know the law, the knowledge of sin. But the deed of Jesus is what leads us to the will of the father. If, by the law, a sin is equivalent to something, with Christ, sin is equivalent to a great love of forgiveness. Thus, makes us walk not with sin, but with Jesus hand in hand with us.