Trinity 8 2022

Matthew 7:15-23

August 7, 2022

Zion Lutheran Church + Nampa, ID


In the Old Testament book of Nehemiah, we read how God’s people returned to Jerusalem after the Babylonian captivity and how the city was to be restored and built up again according to God’s Word.  Nehemiah does an inspection of the ruined city, and moved by God’s Word, they start to rebuild the wall around the city.  Now, as you can imagine, this made some of the surrounding nations upset, and Nehemiah was mocked by the Samaritans, Arabs, Ammorites, and Ashdodites. When that didn’t stop the building of the wall, they planned to attack the city, knock down the walls, and scatter the people again.  When Nehemiah heard about their plans to attack, he ordered that those who were doing the construction should carry a sword, spear, shields. Half the workers would then be on guard duty while the other half built, and then they would switch places.  The laborers who carried away the rubble of the ruins were to work with one hand and hold their weapon with the other in case of attack, and they were urged to remember the Lord, to defend their brothers and sons and daughters and wives and homes, and if the rallying trumpet was sounded, to gather for defense with the knowledge that God Himself fights for His people (Nehemiah 4). 

In our Gospel reading for this morning, Jesus shows how He comes not only to suffer and die upon the cross, to pay for the sins of the world, but to admonish and warn and even guard the building up of His Church, which takes place according to His Word as the only begotten Son of God.  Christ teaches us the same truth that He taught His people 2500 years ago in the rebuilding of Jerusalem, that we are to rally to Him and believe that in Christ, God fights for His people. With one hand, He builds up the Church by means of the Gospel through the forgive sins, to grant mercy and protection and guidance, and with the other He reaches for His sword and drives away everything that seeks to tear down the spiritual Jerusalem that He is building. Jesus warns that these spiritual attacks happen in two ways: through false prophets preaching false doctrine, workers of lawlessness; and the bad fruit which comes from their diseased tree. 

Beware the false prophets, Jesus says.  A prophet has one main job and that is to speak the word of the Lord.  He first hears what God says, then he speaks what God says, for the building up, the edification, of God’s holy people, the Church, the spiritual Jerusalem. We heard today from the Prophet Jeremiah, speaking God’s Word about false prophets, that they speak visions of their own mind, filling with vain hopes, refusing to speak God’s judgment on sin, prophesying the deceits of their own hearts.  God does not look kindly on those who speak lies in His name, or those who fail to speak His word faithfully.

This means that doctrine actually matters; what we believe, teach, and confess is a matter of life and death.  One of the most dangerous things that you can do as a Christian is to act of if our differences don’t matter.   They do; they matter to Jesus, and they should matter to you. It matters what you believe about baptism.  It matters what you believe about the Lord’s Supper.  It matters what you believe about salvation, forgiveness, grace, faith, and how you answer Jesus’ question: “Who do you say that I am?” It matters who and what you listen to, what kinds of shows you watch, what kind of school you send your children to.  Every Christian must be vigilant against false prophets, false teachers, false messages from the world and from the devil so that you are not seduced into misbelief. Mark and avoid false prophets; they seem good, but they are deadly. Pick up the sword of the Spirit, the Word of God, and guard your souls. St. John says in 1 John 4:1 to not believe in every spirit, but test whether they are from God, St. Paul says in 1 Thessalonians 5:21, “Test all things, and keep what is good.”

But how do you know?  Jesus says they are wolves dressed in sheep’s clothes, so it’s hard to tell by how they look.  The false prophet’s outward piety is used to disguise their false and deadly teaching. They appear to be righteous, but their hearts are far from the Lord.  For one only belongs to Christ’s true flock when clothed in Christ’s righteousness, that covers all sin; this isn’t a costume or a disguise, but it’s an identity based on which shepherd one belongs to.

And so Jesus says, you will know them by their fruit; that is, by the content of their message, which comes from the roots and trunk of their faith.  But this still isn’t that easy.  A piece of fruit may look good on the outside, it may look ripe, but the only way to tell is to look deeper to see if it has been eaten by a worm or rotten to the core. Look at the tree, the source of what is being said.  If the tree is diseased, so will the fruit be. 

The obvious bad fruit is easy to see, that which outright contradicts God’s Word; the harder part is that which appears good but is rotten.  Which means sometimes you’ve got to go deeper than the surface and you’ve got to look at the source of the fruit, at the tree, to see whether it is healthy or diseased. In other words, you’ve got to judge whether what is being said matches with God's Word revealed in Holy Scripture; whether the one who presumes to speak for God is taking God seriously, at His Word, believing and confessing Christ and Him crucified. So the author of Hebrews begins his letter, “Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son…” (Hebrews 1:1-2).  And St. Paul says, “Faith comes by hearing, hearing the message of Christ.” The message about Christ and by Christ. The point is this: everything must be judged according to the Word of God, which is the source of the Christian faith as it flows from the mouth of God.  

All these things are wrapped up together: the Lord God, His holy Word, right faith, right practice and worship, the true Church built up by Christ upon the foundation of the prophets and the apostles, and eternal salvation.  False teaching on part of doctrine leads to false beliefs in many others. Sincerity, assertiveness, charisma; casting out demons and miracles, don’t make a teaching or a teacher true or faithful.  Jesus is clear, not everyone who says “Lord, Lord, will enter the kingdom of God.  True prophets must be those who hold to Christ’s revealed Word, who do not take away from it or add it to, but builds His life to it through faith in Jesus Christ crucified for the forgiveness of sins.  The man who builds on Christ does and has what he hears from Him.