Christians, however, also need the Law as a norm, i.e., as rule and guideline from which they learn how they should walk in a God-pleasing way. Certainly not, however, in so far as they are reborn or Christians. To this extent, they have the Law of God within themselves and need no external rule and guideline for their manner of life. In this place belongs the word: “The Law is not laid down for the just.” But inasmuch as Christians still have the flesh in themselves, blindness and perversity prevails in them regarding the will of God. They want to do things that God does not require of them, and the things they should do they want to omit.
The history of the Church and of every Christian life provides enough examples. Just think of monasticism. Men came and come to the strange delusion of wishing to serve God by leaving their vocation and running to the cloister. Let us remember that in ourselves, i.e., in our flesh, we often have little desire for the works of our vocation, but we may be content with the things that are not commanded us.
Therefore, we cannot seriously stress enough that the Law must be incessantly taught in the Church as the norm of a God-pleasing life. To the same people to whom the apostle said: “Christ is the end of the law” he holds up before them: “Let us walk properly as in the daytime, not in orgies and drunkenness, not in sexual immorality and sensuality, not in quarreling and jealousy. But put on the Lord Jesus Christ, and make no provision for the flesh, to gratify its desires.” Further: Paul certainly gives Christians the testimony that they gladly give. He testifies to the Christian communities that they “gave according to their means and beyond their means, of their own accord”, and again: “I know your readiness” — and yet the same apostle holds up before the same people as rule and norm: “God loves a cheerful giver”, and reminds them: “The point is this: whoever sows sparingly will also reap sparingly, and whoever sows bountifully will also reap bountifully.” From this we see that we merely follow the apostolic model when we hold up the Law to Christians as the norm that shows them what they are to do.
Let us see to it that in this point no antinomian practice creeps in among us. Someone might think that all external substance has no value before God. That is why I will continue with the preaching of the Gospel, but keep silent of the Law as the norm of the Christian way of life. I will wait for true works to come by themselves. That would make a false distinction between Law and Gospel. This would in practice neglect a part of the Word of God. It is true that a Christian, as a Christian, is not only willing to walk in God’s commandments, but as a Christian he also knows himself (namely because the Law is written in his heart according to the new man), what is the good will of God. But a Christian is a double person [German: Doppelmensch]. He still has the old man in himself who always indicates the wrong way regarding works. But because the old man does not live apart from the Christian or is removed from him, but dwells in the Christian, and forms a person with him, he thus continually obscures the right knowledge of what the will of God is to the Christian. For this reason, the Law of God must still be held up before Christians as the norm of a God-pleasing life.
Franz Pieper, “The Practical Importance of the Proper Distinction of Law and Gospel”
Note: Italicized print is Pieper’s emphasis. Bold print is my emphasis.