Two of the complaints that have arisen in response to the recent posts on preaching the law "Are you an Antinomian," "Luther in the Antinomian Disputations," "Some thoughts on Law & Gospel Preaching," and "Good example of exhortation," is that to preach the law in a manner so as to exhort to good works, especially after having preached the gospel, is to forget that 1) we are simultaneously sinner and saint (the simul), and 2) the law always accuses. I'd like to look at these briefly and ponder their merit.
We know from the Scriptures and the Confessions that the new man in Christ delights in the law of the Lord. It accuses him not. For in Christ, who is the fulfillment of the law, the new man also has fulfilled the law of God perfectly and completely (FCSD V and VI).
We know also from the Scriptures and the Confessions that the old man must be put to death by daily contrition and repentance. He is a recalcitrant donkey who needs to be prodded, pushed, and pulled, even threatened to do what is good and right. The law then accuses because the old man still clings to the flesh (FCSD V and VI).
I think we who have been hashing this out, sharpening one another as iron sharpens iron, agree on both these statements. What we have been seemingly disagreeing about is whether it is proper to end a sermon with a use of the law as exhortation to good. The above posts have argued that yes we should. Others have disagreed (You can read this in the comments). The reason one must not preach the law as exhortation to good after you have freed them with the gospel is that it binds those who are free or worse heaps more chains on those who are already bound. This is so because you must remember the simul because the law always accuses. So the argument, as I've understood it, is that if you preach the law as exhortation to good you at the end of a sermon you have forgotten the simul because the law always accuses and thus have bound those who are free.
Now it seems to me that it is not those who encourage exhortation who have forgotten the simul, but those who reject it. Here is why.
The new man delights in the law of the Lord. He meditates on it day and night. He hears it with joy and a glad heart.
The old man chafes under the law, as well he should. For it accuses him constantly. There is no reformation of the old man. He can not be made better. He needs to be killed. He needs to be drowned. He must die. But the old man is a good swimmer. And he continues to cling in the flesh. So he must be continually killed. He must continually be made with the bit and bridle of the law to be prodded, pushed, and pulled, even threatened to do what is good and right. And that is the law's job, not the job of the gospel.
The gospel frees men from their sin so that a new man might arise in them to live before God in righteousness and purity forever. The gospel frees men from their sin so that they might hear the law of God as it was intended to be heard, so that they will rejoice in it. That is to say, to preach exhortation to the Christian at the end of a sermon, takes into account both natures in him, the new man and the old man alike. It preaches what the new man will rejoice in, and it preaches what must force and kill the old man who will use even the most precious gospel as license to do what he ought not to do.
Refraining from this preaching of the law, the preaching of exhortation to good, forgets the simul in that it fails to recognize either that the old man in the Christian will stop at nothing to use freedom for sinful advantage or that he is in someway no longer present and needs to be killed. If the old man is further bound, if more links are added to the chains that weigh him down in the water to kill him, then that is exactly what he needs. And the new man hears the Lords commands with joy. He can't be bound. For he has already fulfilled it in Christ.
So do not be afraid to preach exhortation to good. The law will do what the law does for the Christian, the old and new man alike, by the power of the Spirit attached to the Word.