"The Law always accuses." It is axiomatic in Lutheranism. When the will of God is announced in the ears of His sinful creatures their consciences are stricken with guilt. It cannot be otherwise. Sinners will always stand accused before the Law of God.
Yet I do not think we preach like we believe this. We preach more as if we are afraid that the Law will fail in its accusations, so we have to do that work, even if that means leaving out the Law's other functions.
"The Law always accuses, but it does not only accuse." It also acts as a curb for evil in the world, threatening would-be thieves, murderers, and adulterers with proper punishment. If you live by the sword you will die by the sword. There is no honor among thieves. The house of the adulteress sinks down to death.
The Law too imparts wisdom to the child of God, teaching him the works that God desires of him. He learns what is true, honorable, just, lovely, commendable, excellent, and praiseworthy. He must be taught, for though his new heart washed in the blood of Jesus desires to do good, it does not know what good to do.
If we believe that the Law always accuses, then it would follow that we can trust it to do that work while the Law is being proclaimed and taught without our aid, or at least without very much. Our Law preaching should be primarily focused on the content of the Law, the actual commands, rules, and virtues that God has put forth as good and right.
Yet far too often our Law proclamation descends into spiritual name-calling. We are content to tell people that their good works are dirty diapers in the sight of God, that they are rubbish before Him. We convince them that they are sinners without convicting them of any sins.
Of this I am certainly guilty. I am in need of deep repentance. The Law must do more than label me as scum. It must show me why I am scum. When God's commands are taught, then I will see clearly that I have failed to keep them.
Only then will I know how much I need Jesus and the redemption that His blood has bought. Only then will I be prepared to receive the forgiveness of my sins. Only then can the Gospel of Christ's action for me restore me to life, forever.
Teach the Law. It will accuse. Proclaim the Gospel. It will restore.