A Guide to Spiritual Fruit Inspection
Introduction: A Tolerant Age's Intolerance of Truth
We live in a squishy age. It is an age that prizes niceness above truth, sincerity above soundness, and a vaguely spiritual "kindness" above all biblical and doctrinal clarity. In such an age, to speak of "false prophets" is considered rude, uncharitable, and frankly, a bit embarrassing. To suggest that we must actually judge a teacher's message and life is to be accused of the one remaining cardinal sin: being judgmental. Our generation has taken one verse from this very chapter, "Judge not, that you be not judged," ripped it from its context, and fashioned it into a club to beat down any and all attempts at biblical discernment.
But Jesus, who is not squishy, will not have it. Right after He tells us to enter by the narrow gate, He immediately warns us that there will be slick salesmen trying to redirect traffic to the broad road. He does not say, "Be nice to false prophets." He does not say, "Assume the best about those who teach another gospel." He says, "Beware." This is a command. It is a sharp, urgent, and loving command. A shepherd who refuses to warn his sheep about wolves is not a loving shepherd; he is a hireling who doesn't care about the flock. He is a coward. True love posts a warning sign. True love is discerning. True love protects the flock from predators.
So Jesus gives us a command to beware, and then He gives us the diagnostic tool. He gives us an infallible test. He doesn't tell us to trust our feelings, or to look for supernatural signs, or to measure a man's charisma. He gives us a plain, objective, agricultural test that any honest man can apply. He tells us to become fruit inspectors. This is not an optional elective for the spiritually advanced. This is basic Christian competence. If you cannot tell the difference between a grape and a thorn, or a fig and a thistle, you are a danger to yourself and to the church.
The Text
"Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves. You will know them by their fruits. Are grapes gathered from thorn bushes or figs from thistles? Even so, every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. So then, you will know them by their fruits."
(Matthew 7:15-20 LSB)
The Camouflage and the Carnage (v. 15)
Jesus begins with the nature of the threat.
"Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves." (Matthew 7:15 LSB)
Notice the two key elements here: deception and destruction. The disguise is "sheep's clothing." This is important. Wolves do not come looking like wolves. They don't announce their heresies from the rooftops. They come looking like one of the flock. They use our vocabulary. They talk about Jesus, grace, love, and community. They carry big Bibles. They have pleasant smiles and a winsome demeanor. The sheep's clothing is a carefully constructed costume of orthodox-sounding language and pious behavior designed to gain access to the flock.
But inwardly, their nature is entirely different. They are "ravenous wolves." This is not a picture of a misguided brother who has a few doctrinal details wrong. This is a predator. A wolf's intention toward sheep is not complicated; it has one goal, which is to kill and devour. False prophets are not interested in the health of the sheep. They are interested in what they can get from the sheep: money, power, sexual gratification, and the ego-stroking applause of a following. Their teaching is not soul-food; it is soul-poison. It leads to destruction. This is why doctrinal purity is not a matter of theological nit-picking. It is a matter of life and death.
The Agricultural Axiom (v. 16-18)
Having identified the threat, Jesus gives us the method of detection.
"You will know them by their fruits. Are grapes gathered from thorn bushes or figs from thistles? Even so, every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit." (Matthew 7:16-18 LSB)
Jesus states the principle twice for emphasis: "You will know them by their fruits." This is a certainty. The fruit reveals the root. He then uses two illustrations from the Palestinian countryside that are so obvious as to be comical. Do you go looking for grapes on a thorn bush? Of course not. The idea is absurd. A plant produces according to its nature. You don't get apples from a poison ivy vine. It is a fixed law of creation.
And so it is in the spiritual realm. A good tree, one that has been made good by the grace of God in Christ, will necessarily bear good fruit. A bad tree, one that is still rooted in the soil of Adam's rebellion, will necessarily bear bad fruit. Jesus intensifies this in verse 18: a good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. This is a statement of spiritual impossibility. A man's life and teaching flow directly from the state of his heart. As Jesus says elsewhere, "out of the abundance of the heart the mouth speaks" (Matt. 12:34).
So what is this "fruit" we are to inspect? It is the total output of a person's life and ministry. We must look at three things. First, their doctrine. Is what they teach biblical? Does it exalt God and humble man? Does it faithfully proclaim the law and the gospel, sin and grace, judgment and redemption? Or is it a man-centered, therapeutic, ear-tickling message that avoids hard truths? Second, we must look at their character. Do they display the fruit of the Spirit: love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control? Or are they marked by pride, greed, anger, sexual immorality, and a refusal to be corrected? Third, we must look at the fruit of their followers. What kind of Christians does their ministry produce? Are they mature, discerning, holy, and humble? Or are they arrogant, divisive, worldly, and perpetually immature?
This is not a call to sin-sniffing perfectionism. Every pastor is a sinner saved by grace. But it is a call to look at the consistent pattern, the trajectory of a man's life and teaching. The nature of the tree will always, eventually, show itself in the fruit.
The Eschatological Bonfire (v. 19)
Jesus does not leave this in the realm of abstract agricultural principles. He connects it to ultimate, eternal realities.
"Every tree that does not bear good fruit is cut down and thrown into the fire." (Matthew 7:19 LSB)
This is the language of final judgment. The axe is laid to the root of the tree, as John the Baptist warned. The issue is not merely one of effectiveness or usefulness in this life. The issue is eternal destiny. A bad tree is not just unproductive; it is fuel. False prophets, and those who follow them down the broad road, are destined for the fire of God's wrath. This is why our discernment must be sharp and our warnings must be clear. We are not playing games here. We are not just debating theological fine points. We are dealing with hellfire.
The Unmistakable Conclusion (v. 20)
Jesus concludes by repeating the main point, driving it home like a nail.
"So then, you will know them by their fruits." (Matthew 7:20 LSB)
The conclusion is inescapable. Do not be fooled by the sheep's clothing. Do not be taken in by charisma or credentials. Ignore the packaging and inspect the product. Look at the fruit. The test is objective, it is observable, and it is reliable because it was given to us by the Lord of the harvest Himself.
Application: From the Orchard to the Heart
How, then, do we live this out? First, we must apply this test to ourselves. Before you go inspecting everyone else's orchard, take a hard look at your own branches. What fruit is your life producing? Is it the fruit of the Spirit, born of a heart regenerated by grace? Or is it the sour, rotten fruit of the flesh? If you see bad fruit, the solution is not to try harder to be a better tree. A bad tree cannot improve itself. The solution is repentance and faith in Jesus Christ. The gospel is the good news that God, through the death and resurrection of His Son, does not just trim the branches of bad trees. He cuts them down at the root and raises up a new creation in their place, grafting us into Christ, the true vine. Only then can we bear good fruit.
Second, we must apply this test to those we listen to. Be a good Berean. Examine the Scriptures daily to see if these things are so. Do not outsource your discernment. Read the books, listen to the sermons, and watch the lives of your teachers. And if you see the consistent production of bad fruit, bad doctrine, bad character, then you have a command from Jesus: "Beware." Have nothing to do with them. Turn them off. Walk away. Protect your own soul and the souls of your family.
Finally, this is a solemn charge to the elders of the church. Shepherds, your primary duty is to feed and protect the flock. This means you must be willing to identify the wolves and drive them away. Our modern evangelical world is overrun with a sentimental cowardice that calls itself "love" but is in fact a dereliction of duty. To tolerate wolves in the name of tolerance is to hate the sheep. May God grant us the courage and clarity to be faithful fruit inspectors, for the glory of our God and the good of His church.