The Law says it is God's will and command that we should walk in a new life. But it does not give the power and ability to do it. The Holy Spirit renews the heart. He is given and received, not through the Law, but through the preaching of the Gospel. Thereafter, the Holy Spirit uses the Law in order to teach the regenerate from it and to show them in the Ten Commandments what is the "will of God, what is good and acceptable and perfect" (Romans 12:2) in what "good works, which God prepared beforehand, that we should walk" (Ephesians 2:10). He encourages them to this. When they are idle, negligent, and rebellious in this matter because of the flesh, He rebukes them through the Law. So the Spirit carries out both offices together: He slays and makes alive. For His office is not only to comfort, but also to rebuke. For it is written, "when [the Holy Spirit] comes, He will convict the world [which includes the old Adam] concerning sin and righteousness and judgment" [John 16:8]. Sin is everything that is contrary to God's Law. St. Paul says, "All Scripture is breathed out by God and profitable for teaching, for reproof" [2 Timothy 3:16]. And to rebuke is the Law's special office. Therefore, when believers stumble, they are rebuked by the Holy Spirit from the Law. By the same Spirit they are raised up and comforted again with the preaching of the Holy Gospel. (paragraphs 11-14)
Condensed from CONCORDIA: THE LUTHERAN CONFESSIONS, copyright 2005,2006 by Concordia Publishing House. Used by permission. All rights reserved. To purchase a copy of CONCORDIA, call 800-325-3040.