God give you all much grace and peace through the knowledge of God and Jesus Christ,
  our Lord. Amen.
  Beloved Brothers and Sisters in Christ Jesus!
  God's church upon earth has from the beginning been a militant church. It has ever been
  oppressed and persecuted by the mighty ones of the world. Also within the church at all
  times, men have arisen who have spread false teachings and made factions for themselves,
  thus disturbing the church and causing divisions and offenses. In Adam's church there was
  Cain, the self-righteous; in Noah's church, Ham, the despiser of his father; in Abraham's
  church, Ishmael, the mocker; in the church of the prophets, many false prophets preached
  though the Lord had not sent them and they gave the people false comfort and led them into
  the sin of idolatry.
  Even in the apostolic church, in nearly all places where the gospel was preached and
  received, there arose heretics who caused divisions, yes, often disturbed entire
  flourishing congregations. Among these, St. Paul especially names Alexander the
  coppersmith, Hymenaeus, and Philetus; and St. John mentions the whole sect of the
  Nicolaitanes. And so also to this day. Wherever and whenever the pure doctrine has been
  heard, opponents have arisen. Satan has never been able to leave the church in peaceful
  possession of its heavenly treasures. The church therefore has ever had to use God's Word,
  not only as food for the soul, but also as a weapon in unceasing warfare against false
  teachers. If a church cease to strive, it cannot remain a church for long. Just as the sun
  in springtime calls forth not only the good seed, but also weeds from winter's sleep, so
  also, by the blessed preaching of God's Word, Satan is awakened, who seeks to get his
  tares planted among the wheat and thus choke it.
  Now we ask, why does God permit His flock which is to be guarded by its shepherds, also
  to be attacked by wolves, who present themselves as shepherds that they may deceitfully
  capture the sheep and destroy them? God could prevent this. Why does He not do so? Two
  reasons especially are given by God's Word. God permits it partly to prove His children
  and partly to punish the unthankful hearers. St. Paul says to the Corinthians, "For
  there must be also heresies among you, that they which are approved may be made manifest
  among you." If no one ever assailed the pure doctrine, it would never truly be
  manifest who clung to it. But when false teachers and fanatics arise in the church, then
  also those who sincerely care for the pure word reveal themselves. Then the faith of the
  righteous is tested and certified. If pure doctrine were never attacked, the Christians
  would soon become indolent, lazy, and lukewarm. But the more clearly others depart from
  God's Word, the more a Christian is driven to search it diligently and to give painstaking
  attention to each word. The more falsifiers of the word crowd in upon the orthodox
  teacher, the more closely he must examine all, and the more he will therefore grow in
  divine knowledge and assurance. Heretics, therefore, are nothing else than the grindstone
  of the church, whereby it learns to use the Sword of the spirit ever more keenly. Thus by
  the hand of God can good come from evil.
  God often carries out his heaviest judgments through false teachers. God often bestows
  upon the land or a church true teachers for a time. But then it often happens that they
  are despised and received ungratefully. Earthly treasures are esteemed more highly than
  the pure word and sacrament. Men become ashamed before the world because of the pure
  doctrine. Nothing is done to maintain the orthodox ministry. God's word is heard with a
  sleepy mind. Men learn to despise it. Finally God allows such unthankful disciples to lose
  the heavenly treasures, so that they who have despised the precious bread of the divine
  word, shall in retribution be fed with the worthless stones of man-made teaching. Thus St.
  Paul writes concerning the Christians in the last times, "Because they received not
  the love of the truth, that they might be saved. And for this cause God shall send them
  strong delusion that they should believe a lie."
  Therefore, my dear hearers, think it not a little thing, that you now can hear the pure
  word of God every Sunday. I know that I don't preach for you the thoughts of my heart, but
  God's counsel for our salvation, as it is revealed, expounded, and confessed in the
  confessional writing of the orthodox church. I know that when you take to heart, give heed
  to, and keep what I preach to you, you shall be saved.
  Yet my friends, in accordance with my office, I am to be able by sound doctrine both to
  exhort and to convince the gainsayers. It behooves me not only to lead you upon the
  pastures of the gospel, but also to warn you against false teachers. Therefore let me now
  seize the occasion which our gospel for the day offers.
  Matthew 7:15-23: "Beware of false prophets which come to you in sheep's clothing,
  but inwardly they are ravening wolves. Ye shall know them by their fruits. Do men gather
  grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit;
  but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit,
  neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good
  fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.
  Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but
  he that doeth the will of my Father which is in heaven. Many will say to me in that day,
  Lord, Lord, have we not prophesied in thy name? And in thy name have cast out devils? And
  in thy name done many wonderful works? And then will I profess unto them, I never knew
  you: depart from me, ye that work iniquity."
  After Christ had presented the true doctrine, He now, in the text just read, warns
  against false teachers and says to his hearers, "Beware". With these
  words, Christ takes judgment from the teachers and gives it to the pupils. He takes it
  from the shepherds and gives it to the sheep. I therefore present for your devotion that:
  The Sheep Judge Their Shepherds
  I show you
  
    1. That the sheep are the judges;
    2. That therefore they shall know the true doctrine and be steadfast
    in it;
    3. That they must not let themselves be deceived by a mere good
    appearance; and finally
    4. That they must above all look for the proper fruits.
  
  The Sheep are Judges
  Christ says in his sermon on the mount, where not only disciples, but also a great
  multitude were present, "Beware of false prophets 
 Ye shall know them by
  their fruits." This admonition by the Son of God shows us plainly how entirely
  false the principle is that the preachers should teach and the hearers only listen, that
  the shepherds should lead and the sheep only follow, that the clergy should resolve and
  the congregation only acquiesce. No, when Christ calls upon his hearers to beware of false
  prophets and to know the true and the false by their fruits, Christ thereby seats all
  hearers upon the seat of judgment, placed the balance scale of truth in their hands, and
  bids them confidently execute judgment on their teachers.
  All that is taught in the church of Christ concerns our soul's salvation. In these
  matters no one shall be dependent upon some other person. No one shall establish his faith
  upon another person. Each one shall live in accordance with his own faith, and only by his
  faith be saved. No other person can die for us, no other person can appear in our stead
  before God. No other person can stand before his judgment seat in our place. Everyone
  shall sometime answer to God for his own faith and his own life. Then he will not be able
  to refer to another and say, This one or that one taught me thus and I have believed and
  followed him. No, in matters which concern your soul, you shall not look with the eyes of
  another person, but with your own eyes. If you permit yourself to be deceived, you have
  deceived yourself. The responsibility is yours. God says, certainly, that he will demand
  at the hand of the false teacher, the blood of those he has led astray, but he says also
  that the deceived one shall die because of his sin. (Cp. Ezekiel 3:17-21; Ezekiel 33:1-9).
  In God's Kingdom we are all equal. Holy Baptism takes the purple from the king, and the
  rags from the beggar, and clothes them both in the robes of Christ's righteousness. In
  divine matters it does not depend upon on learning, or holiness, or cleverness, or
  prudence. It often happens, rather, that the most learned are the most perverse. Human
  wisdom is foolishness to God. Human cleverness is to him stupidity. Human righteousness is
  to Him sin. If a learned man would enter heaven, he must climb down from the heights of
  his human wisdom and become a child. For God reveals his mysteries only to the babes who
  humbly acknowledge their natural blindness and darkness. Therefore in divine matters no
  one is excluded from the judicial office. All Christ's sheep are judges, both learned and
  layman, man and wife, bachelor and spinster, young and old, for it concerns each one's
  soul, his own life, his own salvation.
  Therefore we find that even the holy infallible apostle praised the Bereans because
  they did not receive the apostles without testing them, but compared the revelation of the
  New Testament with that of the Old, and daily searched the writings of the prophets to see
  whether matters were as preached by the apostles. Also St. John advises his hearers:
  "Beloved, believe not every spirit, but try the spirits whether they are of
  God". But above all it is noteworthy that St. Paul writes to the Corinthians whom he
  had several years before brought to the faith, "I speak as to wise men, judge ye what
  I say." You see then, my dear ones, God does not desire that you shall, without
  testing, receive either a human book, or a human lecture, or a human resolution, or
  instruction. You shall let no man rule over your conscience. "One is our master, even
  Christ." Such matters are not to be decided by majorities. At the famous ecumenical
  church meeting at Nicea, there were three hundred eighteen orthodox bishops gathered from
  the whole world. Three hundred seventeen wanted to resolve to forbid the marriage of the
  clergy. One only, and he a bachelor by the name of Paphnutius, arose against all, showed
  from God's Word the propriety of the marriage of the clergy, and because of this one
  voice, all three hundred seventeen bishops withdrew their vote and the one vote prevailed.
  Oh, my dear friends, if you at one time had realized that the office of judge belonged
  to you, you would not have entered upon so many and such dangerous bypaths. Your preachers
  went on false paths and you followed without testing, in false confidence in man. How
  sorrowful the consequences have been. Therefore know and protect your right. "Prove
  all things and hold fast that which is good." But this leads me to the second part of
  our consideration, namely this, that if the sheep are to judge the shepherds, then they
  should also know the true doctrine and be sure of it.
  The Sheep Shall Know the True
  Doctrine and Be Steadfast in It
  Even in secular, temporal matters a judge dare not pass sentence arbitrarily; nor may a
  sworn juryman do that; for there is a lawbook by which men are to judge. He who rules in a
  state according to his own desires is called a tyrant. There the innocent finds no refuge,
  the criminal receives no punishment. If it be so in the state, it is even more so in the
  church, where not secular and temporal matters, but spiritual and divine matters are at
  stake.
  To be sure, it is the holy, inalienable and unassailable right of the whole
  congregation and of every member to judge doctrine, to prove it, to receive it or reject
  it. But in the church no one is to rule and control with force  not even the
  congregation. Christ says, "Ye know that they which are accounted to rule over the
  Gentiles exercise lordship over them; and their great ones exercise authority upon them.
  But so shall it not be among you: but whosoever will be great among you, shall be your
  minister: And whosoever of you will be the chiefest, shall be the servant of all."
  Neither shall the congregation give orders. It shall not say, this is our will, this we
  command; thus it shall be, for we are many and we have the power. No, not man, but God,
  Jesus Christ, his holy Word alone shall rule among us. As it is written in the 82nd Psalm,
  "God standeth in the congregation of the mighty; he judgeth among the gods." Or
  as St. Peter says, "If any man speak, let him speak as the oracles of God." In
  the church no one sits upon the throne but Jesus Christ; He is the head of the church, the
  Chief Shepherd, the Lord, the Master, the Judge; and all the church sits at His feet and
  judges as lesser judges in accord with the Lawbook of its heavenly Monarch.
  With respect to love, we are one another's debtors, servants, and slaves; but with
  respect to faith, no one is another's slave. They all are slaves only of Christ, subject
  to His most holy Word, as the only and unchangeable rule and guide. All shall bow before
  this Word, shepherd and sheep. In accordance with this Word, all, whether teachers or
  hearers, shall permit themselves to be judged.
  Since the sheep are to be the judges of their shepherds, you see that each Christian is
  hereby seriously admonished to search daily in the Scriptures, so that he can separate the
  true from the false and gold and silver from hay, straw, and stubble.
  Give earnest consideration then, my friends, to the fact that you are called to the
  office of judge in the congregation. Become ever better acquainted with the Lawbook in
  accordance with which you shall judge. Use daily diligence that you may be ever better
  acquainted with the pure doctrine in order that you may be ever more capable of using the
  divine scale, the divine rule, and touchstone. Do not despise diligent searching in the
  Holy Scriptures, in the books of orthodox teachers, and especially in the public
  confessional writings of the orthodox Lutheran church. Don't think that you lack time,
  that you must look out for your earthly calling. The salvation of your soul is concerned.
  Should you not have time for that? If you would be true judges in the church, you must not
  only regard the pure doctrine of God's Word as more dear and more precious than anything
  else in the world, you must also be so firm in your doctrine that you would rather die
  than depart from it by so much as a letter. You must be so faithful that you do not ask if
  the learned ones, the wise ones, the esteemed ones are on your side; for your faith shall
  not rest upon the authority of men, though they be ever so holy and wise, but alone upon
  the infallible Word of God. From the heart you must be able to say with the disciples,
  "Lord, to whom shall we go? Thou has the words of eternal life, and we believe and
  are sure that thou art that Christ, the Son of the living God."
  Why is it that so many Lutherans now turn to the sects? It is because they have not
  known the teaching of their church, or if they have known it, because they have accepted
  it, not on the basis of God's Word, but only on the recommendation of others. Such people
  let themselves be "tossed to and fro and carried about with every wind of
  doctrine."
  But here many will perhaps say, I am so weak in knowledge, how shall I test the
  teachings? You also, my dear Christian, have been cared for. You have Luther's Small
  Catechism. There you have a glorious summary of the whole Christian faith and its chief
  articles. What is not in accord with that you can boldly throw out, you make no mistake.
  All that is necessary for you to know for your salvation and for the testing of the pure
  doctrine is found briefly and simply in your Catechism. In the first part you learn of
  true God-pleasing works. In the second part of saving faith, in the third of proper
  acceptable prayer, and in the fourth, fifth, and sixth of the true sacraments and the
  Office of the Keys. In the table of duties you learn the true Christian attitude toward
  your calling and condition.
  Yet, my friends, Christ cautions His hearers that they should not let themselves be
  deceived by a mere good appearance, and that is the third thing of which I now speak to
  you.
  The Sheep Must Not Let
  Themselves Be Deceived by a Mere Good Appearance
  Christ says, "Beware of false prophets, which come to you in sheep's clothing, but
  inwardly the are ravening wolves." There are, my hearer, especially in this last age
  of apostasy, persons, who though baptized to Christ, deny his deity and atonement. They
  mock the Triune God and declare the most holy Bible to be a book of fables. These are
  wolves in wolves' clothing. If a person be led astray in his faith by their mockery of the
  Most High, then he must certainly have previously lost the true faith from his heart and
  have willfully turned away from God. A Christian can surely guard himself from such
  prophets of Satan.
  Christ does not properly speak of such false prophets in our Gospel. They are not the
  only ones against whom a Christian must be on guard. No, dear Christians, if you would be
  safe against deception, then realize that the most dangerous false prophets are those who
  have a good appearance. When Satan would lead astray the children of God, he clothes
  himself like an angel of light. When the wolf would enter the sheepfold, he puts on
  sheep's clothing.
  Christ would say this: True prophets in all their teaching appeal to the Word of God.
  If then you meet a man who appeals to God's Word, who also in many cases teaches the
  divine truth, who asserts that he proclaims nothing but the pure doctrine of Scripture,
  then do not trust him immediately, but take care lest this be only sheep's clothing. All
  heretics in the church without exception have appealed to the Scriptures. Even the prince
  of darkness, when he would tempt the Son of God, said, "It is written," but the
  Lord answered, "It is written again." If then the Scriptures be appealed to,
  take care. Compare Scripture with Scripture and you will soon discover the enemy.
  True prophets do not propose themselves as teachers, or force themselves on people, but
  they are regularly called by the Christian congregation. Now if you hear a preacher appeal
  to his office, which God has commanded him to administer, you shall of course not reject
  his office, for that remains powerful and valid, even if a Pharisee or Sadducee administer
  it. But do not let yourself be deceived by it. Take care that the office of the preacher
  be not sheep's clothing. The call can be right and yet the teaching can be wrong. If those
  who are rightfully called become wolves, Christ bids us flee from them.
  True prophets shall lead a godly life. They shall be examples to the flock. If you see
  a preacher, who is friendly to all, pleasant to those who offend him, charitable to the
  poor, helpful to the unfortunate, zealous in his office and calling, honorable in his
  life, unselfish in his endeavors, then certainly you should not reject all this. But take
  care, that this be not merely sheep's clothing. A teacher's life can be blameless before
  men, the while his teaching is ruinous. But what good will his hypocritical life do, if
  his preaching lead you away from the simplicity in Christ? Alas, innumerable inexperienced
  persons, beholding an appearance of holiness, zeal, love and humility, are at once
  thoroughly convinced that there the doctrine must also be true and Christian. They behold
  the beautiful sheep's clothing, deliver themselves to the world hidden under it, and thus
  permit their souls to be torn asunder and destroyed.
  True prophets, finally, are often equipped by God with great spiritual gifts. You may
  hear a preacher who has great glittering gifts. His discourse moves the hardest hearts. He
  enthuses the most sluggish dispositions and moves them to great zeal in pious practices.
  With fascinating oratory he can move souls to tears, or he shows a deep insight in the
  system of Christian doctrine. He can lift up the depressed, comfort the sorrowful, and
  with striking arguments meet the unbeliever. If you see this you must not let yourself be
  deceived by it. Also false prophets are often in possession of great natural gifts. Take
  care that this be not sheep's clothing to deceive you.
  You see that though the appearance of God's Word, the office and call, the holiness of
  life, and finally the fruits of the Spirit be ever so impressive, yet Christians are not
  to let themselves be deceived thereby. "Beware," Christ says, "of false
  prophets, which come to you in sheep's clothing, but inwardly they are ravening
  wolves." But he adds, "Ye shall know them by their fruits." This suggests
  the fourth matter which we should take up in considering the judgment of the sheep over
  the shepherd, namely that they must above all look for the proper fruits.
  The Sheep Must Above All Look
  for The Proper Fruits
  With these words Christ would certainly seem to teach that the true prophets are to be
  recognized by their good deeds, but this only seems to be so. When Christ in our Gospel
  speaks of fruits which a teacher shall bear, then these are not first and foremost the
  fruits of life, but the fruits of doctrine. If a teacher does not bear the fruit of pure
  teaching, he is a false prophet, though he be a Paul or an angel from heaven. No one is
  sent by God except he who proclaims his dear son, Jesus Christ, as the only way of
  salvation for poor sinners. For it is the heavenly Father's will "that everyone which
  seeth the Son and believeth on him, may have everlasting life." And St. John says,
  "Every spirit that confesseth that Jesus Christ is come in the flesh is of God; and
  every spirit that confesseth not that Jesus Christ is come in the flesh is not of
  God." He is a true prophet, who as a called teacher obeys this command of God to
  proclaim his dear Son plainly before the world and lay this foundation correctly, for
  "To him give all the prophets witness, that through his name whosoever believeth in
  him shall receive remission of sins." But where souls are not helped by the plain
  preaching of Christ, there are false prophets, though they be ever so wise, and ever so
  gifted and ever so holy. For Christ says, "Many will say to me in that day, Lord,
  Lord, have we not prophesied in thy name? and in thy name have cast our devils? and in thy
  name done many wonderful works? And then will I profess unto them, I never knew you:
  depart from me, ye that work iniquity." Where false prophets have arisen, there has
  always been this deficiency. They have not proclaimed Christ alone, who of God is made our
  wisdom, righteousness, sanctification, and redemption. But where this article has been
  kept pure, there all soul destroying errors have had to depart as the mists before the
  sun. When you learn from a teacher's sermons how you can come to Christ, how you can abide
  with Christ, suffer with Him and die a blessed death through Him, then you have a true
  prophet. For if you find Christ, you find enough. If you have Him, you have everything.
  A pious life without pure teaching does not make of a preacher a true prophet. But on
  the other hand, the godly life of an orthodox preacher is a most glorious confirmation and
  adornment of the pure doctrine. The good works of a false preacher are like the
  short-lived blossoms on thorn bushes. But the good works of an orthodox teacher are the
  good fruits of a good tree. For, "A good tree cannot bring forth evil fruit, neither
  can a corrupt tree bring forth good fruit."
  Where the pure doctrine is preached, there certainly most hearers do not take it to
  heart. But at least some few will become fruitful trees of righteousness and bear the
  fruits of the Spirit, which are "love, joy, peace, long-suffering, gentleness,
  goodness, faith, meekness, temperance." Where false prophets rule, there they
  certainly also often show one another much love, but is a sectarian love. They love only
  those who belong to their party. But where God's love is shed abroad in men's hearts by
  the true gospel, there men love as their brethren all those who love Jesus Christ, and
  they love as their fellow-redeemed all men, including the wayward and the fallen.
  Now then, my precious brothers and sisters in Christ Jesus, "Beware of false
  prophets which come to you in sheep's clothing, but inwardly they are ravening wolves. Ye
  shall know them by their fruits." Amen.