If you wish to be an orthodox teacher, you must present all the articles of faith in accordance with Scripture, yet [you] must also rightly distinguish Law and Gospel.
This article is about as controversial today as it was in Walther’s day, 130 years ago. With modernity, the self-discovery of Truth was its ultimate goal, however, it was seen as arrogant to claim “I have found the truth”. Today this claim is even called into greater question as modernity’s never ending quest for the self-discovery of Truth has resulted in the bold postmodern claim that Truth as Truth does not exist. Thus we can know nothing with certainty.
This of course is because both in our age and in Walther’s age, epistemology (the theory of how we come to know something) is and was entirely human-centered (anthropocentric epistemology is the $2.43 phrase if you want to really impress your friends). Against this we confess the Holy Scriptures to be God’s revealed, inspired, written Word. That is to say, we can be certain of what Holy Scripture says, even against what we may be able to deduce from our reason and observation.
It is with this firm foundation of God’s revealed Truth (John 17:17 – “Your Word is Truth), that we can actually assert. Therefore, if there is Truth, there is also falsehood, and Walther in this thesis explains how falsehood undermines the whole lot as he points to Galatians 5:9, “A little leaven leavens the whole lump.” A faithful teacher thus must take great care to not introduce even a small amount of false teaching.
The second part of this is that even when all articles of faith are correctly presented, the teacher must be careful to also distinguish Law and Gospel. This is why, as Walther points out an erring preacher may say “It is all by grace” and then follow it by saying “We must do good works.” Both statements are correct, however the latter will always condemn, as it shows us our sin even as it instructs us.
Finally, Walther closes by instructing his students (future pastors) to take care to not just perform a doctrinal dump in their sermons, but to give just the right portion at the right time (like a careful apothecary) and also to take great care not to mix Law and Gospel, which is poison for the soul.
As I read this, it also came to mind the important task of the person sitting in the congregation to listen intently to the entire sermon. If one should walk out of the room or dozes off while a preacher unpacks the Law of the text they may get the impression that all their pastor wants for them is to do this or do that, which as he said, they haven’t been doing and leave crushed by the Law. It is also an important task for the listener to listen to what the preacher actually says, if there is something that wasn’t clear due to the state of the person’s instruction or their lack of attention, a good recommendation would be to ask for clarification. This last piece of advice is a double edged sword as it also places the responsibility for the preacher to be clear in his preaching. Even the most unlearned and minimally instructed should be able to grasp with faith the promises of God presented in a sermon.