Lesson 18: By Their Fruit
The Sermon on the Mount: Matthew 7:15-20
Thank you for taking the time to join me today as we reflect on Jesus’ words together. My prayer is that this study of Matthew 7:15-20 would bring clarity, conviction, and encouragement to your life as a disciple of Christ.
The Danger of False Prophets
As we approach the closing section of the Sermon on the Mount, Jesus addresses a critical pastoral concern: the presence and danger of false prophets. In Matthew 7:15, he warns: “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves.” The image is both vivid and disturbing. These are individuals who outwardly appear benign, even pious, but inwardly harbor predatory motives. Jesus doesn’t say if they come, but when. False teachers have always plagued the people of God (Jeremiah 23:16-22; Ezekiel 13:1-16), and the flock must remain vigilant.
The metaphor of wolves in sheep’s clothing reminds us that deception is a primary strategy of the enemy. The danger lies not only in false doctrine, but in the false teacher’s ability to mask their nature. As disciples and under-shepherds, we must heed this warning with deep sobriety. John Calvin noted, “Nothing is more difficult to detect than hypocrisy, which assumes the guise of godliness.”
Disciples, in exercising their call to shepherd those entrusted to their care, are called not only to feed the sheep but also to protect them. That requires discernment, a virtue too often neglected in the name of charity or inclusivity. Yet true love for the flock requires clarity and courage. As Paul told the Ephesian elders, “Fierce wolves will come in among you, not sparing the flock” (Acts 20:29).
The Test of True Teaching
How are we to recognize these wolves? Jesus gives us the test: “You will recognize them by their fruits” (v. 16). The fruit metaphor is central to Scripture’s portrayal of character and conduct. A person’s inner life eventually manifests in their outer actions, just as the nature of a tree is revealed in its fruit. “Are grapes gathered from thornbushes, or figs from thistles?” Jesus asks. It’s a rhetorical question, and the answer is obvious.
Verses 17-18 drive the point home: “So, every healthy tree bears good fruit, but the diseased tree bears bad fruit.” In Greek, the word for “healthy” (kalon) implies integrity or wholesomeness, while “diseased” (sapron) conveys rot or decay. A false teacher may be persuasive, charismatic, or even outwardly successful, but the enduring fruit of their life and teaching will eventually betray them.
Martyn Lloyd-Jones rightly said, “The ultimate test of all teaching is not the attraction it has for people but the kind of life it produces.” Does the teaching foster godliness, humility, repentance, and love for Christ? Or does it promote self-indulgence, pride, confusion, and division? The fruit will tell.
The Final Verdict
Jesus concludes this section with a severe warning: “Every tree that does not bear good fruit is cut down and thrown into the fire” (v. 19). This isn’t hyperbole. The imagery echoes John the Baptist’s earlier warning (Matthew 3:10) and points to the eschatological judgment that awaits those who lead others astray (cf. 2 Peter 2:1-3; Jude 12-13). God doesn’t treat spiritual deception lightly.
The church must take this seriously. This isn’t a call to be suspicious or harsh, but to be discerning and faithful. Jesus’ closing words in this section reiterate the key principle: “Thus you will recognize them by their fruits” (v. 20). Sound doctrine will produce sound disciples. False doctrine, no matter how polished, leads to destruction.
John Wesley warned his preachers: “Preach not the law without the gospel, nor the gospel without the law.” False prophets often overemphasize one truth to the neglect of others. A healthy tree, by contrast, produces the full counsel of God in the lives of its hearers (Acts 20:27).
Key Principles
False prophets are deceptive in appearance but destructive in effect. They disguise themselves with spiritual language and outward religiosity, but their motives and outcomes are harmful (Matthew 7:15).
True character is revealed by the fruit of one’s life and teaching. Just as trees are known by their fruit, so spiritual leaders are known by the impact of their doctrine and conduct (Matthew 7:16-18).
God’s judgment falls on those who lead others astray. The stakes are eternal; discernment is essential, and the health of the church depends on faithful shepherds guarding the flock (Matthew 7:19-20).
Bible Study Questions
What does Jesus mean by calling false prophets “wolves in sheep’s clothing” (v. 15)? What does this teach us about the nature of deception?
How can we balance being discerning without becoming judgmental or cynical?
What is the significance of using fruit as a metaphor for spiritual health in verses 16-18?
How does Jesus’ warning in verse 19 relate to John the Baptist’s words in Matthew 3:10?
According to Acts 20:28-31, how did Paul instruct the Ephesian elders to protect the flock?
In what ways can false teaching manifest in the modern church? What forms might it take?
How can believers grow in spiritual discernment to recognize unhealthy teaching?
What kind of “fruit” should we expect from sound doctrine and godly leadership?
How does this passage prepare us for Jesus’ warnings in Matthew 7:21-23?
Why is it essential to evaluate both teaching and lifestyle when discerning spiritual leaders?
Questions for Discussion and Personal Reflection
Have you ever encountered a spiritual leader whose teaching sounded good but later proved harmful? What did you learn from that experience?
In what ways can you personally cultivate discernment rooted in Scripture and humility?
How does your own life bear fruit in response to the teaching you receive?
Are there any influences - books, podcasts, leaders - you need to re-evaluate in light of this passage?
What role should church leaders play in protecting their congregation from false teaching?
How can your small group or Bible study promote accountability in doctrine and practice?
Do you find it difficult to confront or question problematic teaching? Why or why not?
What’s the difference between disagreement on secondary matters and truly “bad fruit”?
How can we help younger or newer believers grow in spiritual discernment?
What safeguards can you put in place to remain grounded in the truth of God’s Word?
Action Steps
Take time this week to examine the “fruit” of the spiritual influences in your life. Ask: Do these voices lead me to greater love for Christ, deeper repentance, and Christlike character?
Commit to regular intake of Scripture and prayerful reflection. Healthy trees grow deep roots; immerse yourself in the whole counsel of God (Acts 20:27).
Identify one person in your life whom you can gently guide toward spiritual maturity. Encourage them to evaluate the teaching they receive and help them grow in discernment.
Conclusion
Thank you again for joining me today as we examined Jesus’ warning and wisdom in Matthew 7:15-20. My hope is that this lesson will help you grow in discernment, deepen your confidence in God’s Word, and strengthen your ability to shepherd others well. To explore more studies and devotionals that don’t go out via email, be sure to visit Walking Points. If this has been helpful to you, please consider sharing it with a friend and inviting them to subscribe too.