“By Their Fruits You Shall Know Them”

Fr. Scott Haynes

A Meditation on Matthew 7:15–21

“Beware of false prophets, who come to you in the clothing of sheep, but inwardly they are ravening wolves. By their fruits you shall know them. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit, and the evil tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can an evil tree bring forth good fruit. Every tree that bringeth not forth good fruit, shall be cut down, and shall be cast into the fire. Wherefore by their fruits you shall know them. Not every one that saith to me, Lord, Lord, shall enter into the kingdom of heaven: but he that doth the will of my Father who is in heaven, he shall enter into the kingdom of heaven.” (Matt 7:15–21)

Introduction: A Warning for Every Age

Our Lord’s words in Matthew 7:15–21 are neither gentle suggestion nor passing remark. They are thunder on the mountain: “Beware of false prophets.” The verb brims with urgency—beware!—as if Christ were shaking us awake. For false prophets are not relics of ancient Israel; they roam every age, including our own. They appear not in scarlet cloaks brandishing daggers but in the garb of virtue, with lips dripping Scripture and smiles that promise peace.

Picture a forest at dusk. Wolves slink through the shadows, but they have donned fleece. Their eyes glint with hunger as they mingle among unsuspecting lambs. That is the image Christ paints: wolves in sheep’s clothing. The danger lies in the disguise. If only evil looked ugly! But it borrows the vesture of light. St. Augustine’s warning is timeless: “The devil does not show himself as he is. He comes as an angel of light and offers sweetness; but by his fruits you shall know him.”¹

This passage speaks to every disciple, from the fisherman of Galilee to the parent raising children in an age of spiritual confusion. For it confronts us with three questions: Whom do I follow? What fruit do I bear? And do I merely say, ‘Lord, Lord,’ or do I do the Father’s will? Let us walk through this text slowly, drinking from the wisdom of the Fathers and the witness of the saints.

1. “Beware of False Prophets” — Wolves in Disguise

The first word is a command: “Beware.” The danger is not occasional but constant. Origen, that early exegete, wrote: “False prophets are those who speak from their own spirit, not from the Spirit of God, clothing themselves with Scripture but twisting it to their ruin.”² Such men may possess eloquence, charm, even miracles—but they lack truth.

Why wolves? Because wolves devour. False prophets do not merely mislead minds; they consume souls. And their disguise? Sheep’s clothing—symbols of innocence, humility, perhaps even orthodoxy. The Fathers stress this: heresy does not march under banners of evil; it dresses as piety. Tertullian warned, “The more dangerous a poison, the sweeter its taste.”³

Arius: The Sweet Tongue That Poisoned a World

Imagine Alexandria in the early fourth century. A priest named Arius stands before the crowd, his voice like honey. He sings hymns about Christ—catchy, lilting melodies sung in marketplaces and on the lips of children. But hidden in those verses is a dagger: “There was a time when the Son was not.” With that phrase, he denies the eternal divinity of Christ. The flock applauds, charmed by simplicity, unaware that their Shepherd is being dethroned.

Who opposed him? A young deacon named Athanasius—short, dark-skinned, aflame with zeal. While emperors courted compromise, Athanasius endured exile after exile, clinging to the Creed. His cry—“The Son is consubstantial with the Father!”—still echoes in our Nicene faith. But think: millions fell for Arius because they judged by tune, not by truth. The wolf had worn a lamb’s song.

2. “By Their Fruits You Shall Know Them” — Heaven’s Criterion

Christ gives us the test: not words, not wonders, but fruits. Gregory the Great explained: “The fruit of a tree is the end for which it was planted. So, too, the fruit of a man is the end for which he lives.”⁴ A prophet may speak fair, but does his life exhale charity? Does his teaching yield humility, purity, obedience? Or does it breed pride, discord, sensuality?

St. Paul names the fruits of the Spirit: “charity, joy, peace, patience, benignity, goodness, longanimity, mildness, faith, modesty, continency, chastity” (Gal. 5:22–23). Their counterfeits? The works of the flesh: “fornication, uncleanness, dissension, heresies” (Gal. 5:19–20). The two trees grow in opposite orchards.

The Living Gospel of St. Francis

Picture Assisi at dawn. The mists curl over the Umbrian hills as a ragged figure walks barefoot on the dew. It is Francis, once the son of a wealthy merchant, now clad in patched brown cloth, humming praise as he greets the leper whose sores stink in the sun. He embraces the man, presses his lips to corrupted flesh, and feels joy—not revulsion—because he sees Christ. This is fruit. Not polished rhetoric, not self-display, but a life fragrant with love. Later, when he receives the stigmata on Mount La Verna, his body becomes the very vine of Christ. Could such fruit spring from a root of pride? Never. Holiness cannot be counterfeited. It costs blood.

3. The Good Tree and the Evil Tree — Roots of the Heart

Christ deepens the image: “A good tree cannot bring forth evil fruit, neither can an evil tree bring forth good fruit.” At first glance, this seems harsh. Do not saints stumble? Do not sinners sometimes perform noble deeds? Yes—but Christ speaks of principle: sustained fruit reveals the root. As Augustine puts it, “Good works spring from love, evil works from pride. Change the root, and the fruit will change.”⁵

This thrusts us into the interior life. What we are in secret—our loves, desires, choices—shapes what blooms in public. A hollow trunk may glitter with tinsel in summer, but when winter winds strip its branches, the rot shows.

The Prison Cell of St. John of the Cross

Consider John of the Cross, that mystic of the dark night. Imagine a narrow cell in a Carmelite friary at Toledo, winter of 1577. The stone sweats with cold. A man crouches in chains, his body wasted from lashings, his cassock in rags. The friars—ironically his brothers—imprison him for seeking reform. They feed him scraps, mock him as mad. No parchment, no ink—only darkness.

Yet from that darkness, a song: “Where have You hidden, Beloved, and left me moaning?” Out of crushing roots bursts mystical blossom. John does not curse; he composes canticles of love. His “Spiritual Canticle” and “Dark Night” spring from that dungeon, fragrant as lilies in a grave. Why? Because the root was sunk in God. Storms only drove it deeper. Here is Christ’s principle incarnate: a good tree, though beaten by winds, bears sweeter fruit.

4. “Not Everyone Who Says ‘Lord, Lord’” — The Hollow Bark of Hypocrisy

Christ now strikes at presumption: “Not every one that saith to me, Lord, Lord, shall enter into the kingdom of heaven, but he that doth the will of my Father.” Words—even devout ones—are not passports to Paradise. The devil can lisp pieties. St. John Chrysostom warns: “To cry out with our tongues while denying Him in our works profits nothing.”⁶

Think of the Pharisee in Christ’s parable: rosary of words, barren of mercy. Or of Judas, who kissed Christ even as he betrayed Him. Lip-service is easy; obedience costs.

Ignatius of Loyola: Two Banners Unfurled

St. Ignatius grasped this when he penned the “Two Standards” meditation in his Spiritual Exercises. Picture the plain of history. Two armies assemble. At one end, Christ unfurls His banner—a white standard emblazoned with the Cross. His summons: poverty, humility, service. At the other end, Lucifer spreads a black flag of pride, riches, and vainglory. And men—some whispering “Lord, Lord”—flock to the dark host because its music is sweet. The question lances our soul: Which banner do I march under? Words do not decide it; choices do.

5. Practical Lessons: How Shall We Live?

This Gospel is not for speculation but salvation. How then do we guard against wolves, discern trees, and bear fruit that will abide?

a. Root Yourself in the Cross

The Fathers agree: the Cross is the touchstone. Does a teaching lead to self-denial, to love that bleeds? Or does it promise a gospel without Golgotha? St. Jerome remarks, “The false prophet flatters; the true prophet wounds before he heals.”⁷ Beware the voice that soothes pride or softens sin. The way of Christ is narrow, thorned—but it leads to life.

b. Cling to the Apostolic Faith

Cassian said, “The devil’s first stratagem is to sever you from the rule of faith.”⁸ Wolves thrive where sheep stray from the Shepherd’s voice, which today speaks through the Church’s Magisterium. Measure novelties against the Creed hammered on anvil of martyrs’ blood. Truth does not mutate with fashion.

c. Examine Your Own Fruit

Before scanning forests for bad trees, inspect your own orchard. Do my works breathe charity? Or do I traffic in leaves—words, poses, outward piety—while roots rot in pride? Frequent confession is the gardener’s axe cutting decay; the Eucharist is sap surging life. As St. John Climacus wrote, “A tree is known by its fruit, and a soul by its love.”⁹

6. Saints as Living Commentary

The saints exegete Scripture with their lives. St. Dominic battled heresy not with swords but with luminous truth and poverty. St. Catherine of Siena, in an age of papal exile and clerical rot, bore fruit of fearless love, writing letters that jolted pontiffs. They remind us: discernment without holiness is sterile. To spot wolves, become lambs aflame with charity.

Conclusion: The Final Harvest

Christ ends with a sentence that chills: “Every tree that bringeth not forth good fruit shall be cut down and cast into the fire.” Imagine the orchard at dusk. The Gardener walks among the rows, axe in hand. He bends, examines, waits. Mercy stays His stroke, but not forever. One day, the harvest will come. Where will He cast His glance upon me—laden boughs or leafless twigs?

Yet fear need not have the last word. The same Gardener offers grace—the rain of sacraments, the sun of His Word. He would make of us cedars in His courts, vines heavy with grapes for His chalice. But He will not force. The root must cling to Him, or the branch will wither.

A Final Prayer

O Jesus, true Vine, root me in Thy love. Let no wind of error, no frost of pride, blight the orchard of my soul. Keep me from the wolves without and the hypocrisy within. Grant that I may not only cry, “Lord, Lord,” but do Thy Father’s will with joy. And when the Gardener comes seeking fruit, let Him find clusters of charity, pressed sweet for the chalice of eternity. Amen.

Footnotes

1. Augustine, Sermon on the Mount, II.24.

2. Origen, Commentary on Matthew, 14.

3. Tertullian, Prescription Against Heretics, ch. 2.

4. Gregory the Great, Moralia in Job, 33.

5. Augustine, Enchiridion, ch. 121.

6. Chrysostom, Homilies on Matthew, Homily 23.

7. Jerome, Commentary on Matthew, 7.

8. John Cassian, Conferences, II.

9. John Climacus, The Ladder of Divine Ascent, Step 30.