Here is tomorrow's sermon on Matthew 7:15-23, the one-year Gospel for the 8th Sunday after Trinity, which God willing I will preach tomorrow at St. Peter Lutheran Church in Campbell Hill, Illinois.This is awkward. I stand before you for the first time as a guest preacher. You don’t know me, I don’t know you. Your pastor and I barely know each other. He isn’t here to criticize me or to defend himself. And yet the lessons drawn for this week of the church year, oblige me to talk about your pastor, and any preacher or teacher you hear—whether in this church or another, on TV or radio, through the internet or in a book. The question is how to listen to them, how to judge them, how to tell whether they are feeding you or misleading you, how to spot a wolf in sheep’s clothing. You have no personal knowledge of whether I can preach my way out of a wet paper bag, and yet I am here to tell you HOW TO LISTEN TO A SERMON. I can only suggest that you pay careful attention; then, after comparing what you hear to the doctrine you have learned from faithful, reliable, and legitimately called teachers, you can make up your own mind.
Let’s start with half of a verse from Jesus’ Sermon on the Mount. In Matthew 7:18a, Jesus says, “A good tree cannot bear bad fruit.” Suppose that a minister told you that these words mean that infants need not be baptized. He reasons: God creates each of us and gives us our spirits, so we must be born sinless. God would never create anything evil. And if we’re good by nature, we cannot sin. Just like Jesus says in Matthew 7:18a, “A good tree cannot bear bad fruit.” As ridiculous as it sounds, many people are taken in by that very argument. But you should not be. Either because you were taught to know Scripture better, or because you are wise enough to look up passages quoted at you to see whether they are used correctly, you will quickly find the minister was twisting Matthew 7:18. You only need to read the second half of the verse, which says, “Nor can a bad tree bear good fruit.” This doesn’t support the spin that we are born in sinless innocence.
Or step back even further. In Matthew 7:17, 19, Jesus says: “Every good tree bears good fruit, but a bad tree bears bad fruit... Every tree that does not bear good fruit is cut down and thrown into the fire.” Now suppose a minister tells you that Jesus is talking about sins versus good works. Jesus would be saying, “Only sinful people commit sins. Godly people do only godly works.” What do you do? You recall where Paul writes in Romans (3:23) that no one is without sin, even the best among us stumble in our weakness (Romans 7:7ff.). And we also know God is the One who justifies the ungodly (Romans 4:5). He overlooks our sins and declares us righteous for the sake of His Son. If we could not please Him except by doing only good works all the time, none of us could be saved.
But again, when you hear a preacher putting that spin on Jesus’ words in Matthew 7, you are equipped to judge whether he is feeding you or misleading you. Remember the Word of God that you have been taught; or, if you cannot remember, look it up. And observe what else is missing from the context. In verse 15 Jesus says, “Beware of false prophets, who come to you in sheep’s clothing, but inwardly they are ravenous wolves.” Then He says, “You will know them by their fruits,” and so on, until in verse 20 He concludes, “Therefore by their fruits you will know them.” “Beware of false prophets” is Jesus’ topic sentence for that whole paragraph. It tells us what He’s talking about in all those other statements. Taken by themselves, those statements could seem to be about sins versus good works, saints versus sinners. Taken with their topic sentence in verse 15, their meaning totally changes. Jesus is talking about prophets. Which is to say preachers and teachers of God’s Word. And so Jesus’ sermon, like mine, will eventually explain HOW TO LISTEN TO A SERMON.
From the top: Beware. You have been warned. Remember this warning, and be on the lookout. False teachers will come. They won’t be wearing black cowboy hats, or horns, or a sign around their neck that says “Your Enemy.” They will come to you like wolves in sheep’s clothing. There won’t be any visible mark to distinguish them from true preachers. They may seem just as charming and learned and well-spoken and reasonable as faithful preachers and teachers, if not more so. Their manner of life may be exemplary. There may be a certain something about them that you instinctively want to trust or imitate. But Jesus warns us not to be deceived by a handsome face, attractive clothing, a noble character, or a warm personality. You will know them by their fruits.
Now let’s all have our laugh out at Jesus’ mixed metaphor. What could He possibly mean by the fruits of a sheep, or the fruits of a wolf? More pertinent is the question, what “fruits” come from a prophet, false or otherwise? What fruit does a preacher or teacher yield? His fruit is the direction His teachings lead you in your faith and life. If his teachings lead you away from Christ and His doctrine, if they lead you into sins forbidden by God—or even into “good works” not commanded by God—then the fruit is bad and the tree is bad; the man is a false prophet, and you must not listen to him. On the other hand, if his teaching confirms you in the doctrine and way of life you have been taught on the basis of God’s Word, then you must listen to him, support him, cherish him, encourage him, pray for him, and give thanks for him, as though God Himself was speaking to you and opening the doors of Paradise before you.
And now we come to an even tougher question: How are you supposed to tell whether his fruit is good or bad? You really only have two choices: Either to be firmly rooted in the faith once for all delivered to the saints (Jude 3)—so firmly rooted that you can readily tell the difference between truth and false teaching, and can fight firmly for the true faith—or to be like the Jews in Berea, who “received the word with all readiness, and searched the Scriptures daily to find out whether these things were so” (Acts 17:11). If your faith has not yet been planted very deeply and firmly, that leaves you only one option: to be daily and constantly in the Word. Besides the Bible, read as much as you can understand in the Lutheran Confessions, the writings of Luther, and other authors who bear witness to the same doctrine.
Don’t stop learning Christ’s doctrine until you know the biblical answer to every question. If that time ever comes—though it is most unlikely—then keep studying the Word so that you may not forget. And if you love your children, teach them well, so they may be fully armored against false prophets, whether they come to them clothed in the sport coat of a high school science teacher, or in the comely form of a future husband or wife, or in all their busy lives’ tempting alternatives to going to church. If you want to protect them from false prophets, know your doctrine, teach them to know it, and teach them why it matters.
Why? Because you are on a spiritual battlefield. You can’t afford to go without the weapons and armor of a spiritual warrior. The devil is not only a fierce and active foe, but also a wily one. Sometimes he tries to crush us by brute and sudden force, while at other times he works at slowly and quietly undermining us. His aim is to destroy our faith, to take us away from Christ, to rob us of salvation. And when he isn’t beating us into despair through suffering, conflict, pressure and temptations from the world around us, he may be trying to tempt us into complacency and to sneak into our midst without our noticing. Persecution is one of Satan’s bold plays, right out where Christians can see where the evil lies; the only question then is whether we can bear it. But with false teachers, Satan infiltrates the holy of holies, disguised as people we respect and trust. And the seeds of false doctrine that they sow grow into trees whose fruits make us sick, and whose roots and branches tear us apart. They, mind you—the false teachers, not the faithful—cause the divisions that rend the body of Christ, the scandals and controversies that embarrass us, and the doubts that make us even readier prey for the wolves.
The only armor that can protect us is God’s Word. And that’s not just a piece of pious, figurative language. It doesn’t mean idly accepting the status quo. It means constantly grappling with the holy Word, and wrestling strength out of the holy Sacrament. And this grappling with the Word is not like wrestling with a padded dummy that you can easily throw down. It’s more like clinging to a huge rock with nothing but your fingers and toes. If you want to stay there, you need to get as strong and deep a hold on it as you can.
How can you tell whether someone is leading you astray? How can you measure his teachings against the Word of God? In a commentary on this text, Martin Luther answers: “Everyone should see to it, above all, that he is sure of his cause and of the doctrine. In his heart he should be so well grounded in it that he can stick to the doctrine even though he sees everyone on earth teaching and living contrary to it. Anyone who wants to move along in safety simply dare not pay attention to any of the outward masks in Christendom and guide himself by them. He must pay attention only to the Word, which shows us the right way of life that avails before God. For example, you must hold on to the chief part, the summary, of Christian teaching and accept nothing else: That God has sent and given Christ, His Son, and that only through Him does He forgive us all our sins, justify and save us” (LW 21:254).
Again, Jesus tells us: “Many will say to Me in that day, ‘Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?’ And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!’” Even some who call upon Him by name, and preach in His name, will hear that awful sentence. The question for you is whether they spoke according to His Word, whether they led you toward or away from Christ, whether they held up as God-pleasing the works God commanded or ones invented by themselves. Say to yourself as Luther says: “I shall test them where they ought to be tested, as to whether they serve to strengthen my faith in the Word: that Christ died for me; that through Him I may obtain piety and salvation in the sight of God; and that I should carry out my station [in life] and pay faithful attention to it” (LW 21:273–274).
Meanwhile, real prophecy is taking place here. Called by God to serve in an office commanded by God, a man of God stands here every week to proclaim to you the Word of God. And if he doesn’t exactly predict the future, your pastor is called to tell you things that you cannot learn by experience or with the senses. Nevertheless, these things are as true as though God Himself spoke them. Things such as, “Your sins are forgiven.” And as for miracles—how about Baptism? All your pastor does is say the words by which Christ commanded us to baptize, and add water; but miraculously, the water becomes a bath in the Holy Spirit, and you or your baby becomes God’s newborn child. Or how about the Lord’s Supper? We put in bread, wine, and the words of Christ. What comes out is Jesus’ true body and blood, which we can physically eat and drink, and which actually gives us the forgiveness of sins.
A false prophet can indeed give you these things, because these miracles are tied to the office instituted by Christ and the words spoken by Christ. Even an unbeliever could preach the Gospel to you without any additions or subtractions, and so comfort you and build up your faith, though he would not share in the salvation that he brings to you. Jesus does not tell you to look into your pastor’s heart. He tells you to observe his fruits, which is to say, his teachings. What does he tell you to believe? How does he tell you to live? And do these teachings match the right interpretation of Scripture, in which you have been so carefully instructed?
Jeremiah (23:16–19) tells us that God does not want you to listen to false prophets. He means that you should not obey what they teach. Jesus, on the other hand, tells you to listen and to beware. But He tells you this so that you may safely eat of spiritual food, drink the spiritual drink, and take the spiritual medicine that He so richly serves you in sermon and liturgy, in Word and Sacrament. He wants you to feel free to follow the faithful shepherd He has given you, so that through your pastor, Jesus may protect you from wolves and fill you with His precious gifts. Jesus wants you to hear God’s Law in its fullness and purity, so that you know how to live in a God-pleasing manner, and so that you recognize when you are not doing so; and He wants you to hear His Gospel in all its sweetness and power, so that when you falter and stumble along the way, you may not despair but believe that your sins are forgiven through Jesus’ willingly shed blood and through His slain and risen body. And finally, He wants you to be filled with the Holy Spirit, and with the confidence that, as heirs of God and joint heirs with Christ, we suffer with Him, that we may also be glorified together.