The Axe at the Root: The Preaching of John the Baptist Text: Luke 3:1-20
Introduction: History is His Story
We live in an age that is allergic to history. Our modern sensibilities prefer a sentimental, free-floating spirituality, untethered to the gritty realities of time and place. We want a Jesus of our own imagination, a therapeutic advisor who can be neatly separated from the inconvenient facts of history. But the Christian faith is not a philosophy or a set of abstract principles. It is a report of something that happened. It is rooted in the soil of human history, and if you pull up those roots, the whole thing dies.
Notice how Luke begins. He is a meticulous historian. He doesn't start with "once upon a time." He drops anchor in the bedrock of historical fact. He names the emperor, the governor, the local tetrarchs, and the high priests. He gives us six contemporary rulers. This is not window dressing. Luke is making a profound theological claim: the Word of God, the hinge of all history, did not descend into a mythical fairyland. It erupted into our world, into the grimy, corrupt, and politically-charged world of Tiberius Caesar, Pontius Pilate, and Caiaphas. Christianity is not a myth; it is an invasion. The eternal entered time. And because it is historical, it is verifiable. It can be investigated. And it cannot be ignored.
This historical precision is a direct challenge to our modern desire to privatize faith. The gospel is not a private hobby. It is a public proclamation about the true King of the world, a King to whom Tiberius, Pilate, and Herod all owed their allegiance, whether they knew it or not. The arrival of John the Baptist was not a quiet, personal affair. It was a public, political, and profoundly disruptive event. And the message he brought is just as disruptive today. It is a call to radical repentance, a warning of impending judgment, and an announcement that the true King has arrived to set up His kingdom. This is not a message we can trim or domesticate to make it more palatable. It is a message that demands a response, because the axe, John tells us, is already laid at the root of the trees.
The Text
Now in the fifteenth year of the reign of Tiberius Caesar, when Pontius Pilate was governor of Judea, and Herod was tetrarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene, during the high priesthood of Annas and Caiaphas, the word of God came to John, the son of Zechariah, in the wilderness. And he came into all the district around the Jordan, preaching a baptism of repentance for the forgiveness of sins; as it is written in the book of the words of Isaiah the prophet, “THE VOICE OF ONE CRYING IN THE WILDERNESS, ‘MAKE READY THE WAY OF THE LORD, MAKE HIS PATHS STRAIGHT. EVERY RAVINE WILL BE FILLED, AND EVERY MOUNTAIN AND HILL WILL BE BROUGHT LOW; THE CROOKED WILL BE STRAIGHT, AND THE ROUGH ROADS SMOOTH. AND ALL FLESH WILL SEE THE SALVATION OF GOD.’ ” So he was saying to the crowds who were going out to be baptized by him, “You brood of vipers, who warned you to flee from the wrath to come? Therefore bear fruits in keeping with repentance, and do not begin to say to yourselves, ‘We have Abraham for our father,’ for I say to you that from these stones God is able to raise up children to Abraham. But indeed the axe is already laid at the root of the trees; therefore, every tree that does not bear good fruit is cut down and thrown into the fire.” And the crowds were questioning him, saying, “Then what should we do?” And he would answer and say to them, “The man who has two tunics is to share with him who has none; and he who has food is to do likewise.” And tax collectors also came to be baptized, and they said to him, “Teacher, what should we do?” And he said to them, “Collect no more than what you have been ordered to.” And soldiers were also questioning him, saying, “What should we also do?” And he said to them, “Do not take money from anyone by force, or extort anyone, and be content with your wages.” Now while the people were in a state of expectation and all were reasoning in their hearts about John, as to whether he was the Christ, John answered, saying to them all, “As for me, I baptize you with water, but One is coming who is mightier than I, and I am not fit to untie the strap of His sandals; He will baptize you with the Holy Spirit and fire. His winnowing fork is in His hand to thoroughly clear His threshing floor and to gather the wheat into His barn, but He will burn up the chaff with unquenchable fire.” So with many other exhortations he proclaimed the gospel to the people. But when Herod the tetrarch was reproved by him because of Herodias, his brother’s wife, and because of all the wicked things which Herod had done, Herod also added this to them all: he locked John up in prison.
(Luke 3:1-20 LSB)
The Word in the Wilderness (v. 1-6)
The stage is set with a list of powerful men, the movers and shakers of the world. But the Word of God does not come to the palace in Rome or the temple in Jerusalem. It comes to John, son of Zechariah, in the wilderness. This is always God's way. He bypasses the centers of human power and prestige to raise up His own man from the outside. The wilderness is a place of preparation, of stripping away, of dependence on God alone. It is from the margins that God launches His invasions.
"And he came into all the district around the Jordan, preaching a baptism of repentance for the forgiveness of sins..." (Luke 3:3)
John's message has two components: repentance and baptism. Repentance, metanoia, means a change of mind, a complete reversal of direction. It is not simply feeling sorry for your sins; it is a fundamental reorientation of your entire life away from self and toward God. And this inward reality was to be demonstrated by an outward sign: baptism. This was not a brand new ritual. The Jews practiced ritual washings for purification. But John's baptism was different. It was a one-time act signifying a definitive break with the old life and an entry into the community of the repentant, the people who were getting ready for the arrival of the King.
Luke then quotes from Isaiah 40. This is crucial. John is not a freelancer; he is a fulfillment of prophecy. He is the forerunner, the herald sent to prepare the way for the Lord. The imagery is that of royal road construction. When a king was coming to visit a province, the roads were leveled and straightened. The valleys were filled in, the mountains brought low. This is a metaphor for the work of repentance. The mountains of our pride and self-sufficiency must be leveled. The crooked paths of our deceit and hypocrisy must be made straight. The rough places of our hearts must be smoothed. This is the necessary preparation for the King's arrival. God does not come to a people who think they are fine as they are. He comes to those who have been leveled by the preaching of the law.
And the goal of this preparation is cosmic in scope: "And all flesh will see the salvation of God." This is not just for Israel. The salvation that is coming is for the whole world. From the very beginning of the gospel, the universal scope of Christ's kingdom is announced.
Vipers, Fruit, and the Axe (v. 7-9)
John's preaching was anything but seeker-sensitive. He sees the crowds coming out to him, and his opening line is a blowtorch.
"You brood of vipers, who warned you to flee from the wrath to come?" (Luke 3:7)
He calls them the offspring of snakes. This is a direct echo of Genesis 3. He is saying that by nature, they are children of the serpent, not children of Abraham. They are part of the problem. His question is dripping with sarcasm. It is as if he sees snakes slithering out of a field that is about to be set on fire. Who tipped you off? You are running from the fire, but you are not running to God. You are seeking a religious ritual to inoculate yourselves against judgment, but you have no intention of actually changing.
John then exposes their false confidence. They were trusting in their ethnic identity, their covenant pedigree. "We have Abraham for our father." This is the perennial temptation of dead orthodoxy. We trust in our baptism, our church membership, our Christian heritage, our correct theology. John demolishes this. He says God can make children for Abraham out of the stones by the river. God is not dependent on your bloodline. He is looking for faith, and faith is demonstrated by its fruit.
"Therefore bear fruits in keeping with repentance." Repentance is not a feeling. It is a root that must produce fruit. If there is no change in your life, there has been no change in your heart. You can say you've repented all day long, but if you are still living the same way, you are deceiving yourself. And the stakes could not be higher. "The axe is already laid at the root of the trees." Judgment is not a distant, theoretical possibility. It is imminent. The axe is not just threatening the branches; it is at the root. This is not about trimming a few bad habits. This is about the fundamental status of the tree. A tree is judged by its fruit, and a fruitless tree will be cut down and thrown into the fire.
The Practicality of Repentance (v. 10-14)
John's preaching was not abstract. It was intensely practical. The crowds are convicted, and they ask the right question: "Then what should we do?" They want to know what this "fruit" looks like in their daily lives. And John's answers are remarkably down-to-earth.
"The man who has two tunics is to share with him who has none; and he who has food is to do likewise." (Luke 3:11)
To the common people, he preaches radical generosity. If you have a surplus, you are to share it with those who have nothing. This is not a call for state-enforced socialism. This is a call for a heart transformed by repentance, a heart that is no longer clenched around its possessions but is open-handed toward a brother in need.
Then the tax collectors come. These men were despised as traitors and extortioners. They were Jews who worked for the Roman occupiers, and they typically made their living by collecting more than was required and pocketing the difference. John does not tell them to quit their jobs. He tells them to do their jobs honestly. "Collect no more than what you have been ordered to." Repentance for them meant an end to extortion.
Next, the soldiers. These were likely local men in Herod's service, acting as police. They had the power to intimidate and abuse. John does not tell them to lay down their arms. He tells them to stop abusing their power. "Do not take money from anyone by force, or extort anyone, and be content with your wages." Repentance for them meant an end to brutality and greed.
Notice the pattern. John does not call for a withdrawal from society. He calls for a transformation within society. He tells them to live out their repentance in their specific vocations. The fruit of repentance is not found in pious religious activity; it is found in how you treat your neighbor, how you conduct your business, and how you exercise your authority.
The Greater One (v. 15-20)
John's ministry was so powerful that people began to wonder if he was the Christ. But John was crystal clear about his role. He was the best man, not the groom. His entire purpose was to point to another.
"As for me, I baptize you with water, but One is coming who is mightier than I, and I am not fit to untie the strap of His sandals; He will baptize you with the Holy Spirit and fire." (Luke 3:16)
John's baptism with water was external, symbolic. The baptism of the Messiah would be internal, effectual. He will baptize with the Holy Spirit and with fire. This is one baptism with a dual effect. For those who repent, the Holy Spirit is a purifying, life-giving fire. For those who do not, it is a fire of judgment. There is no neutrality. The arrival of the King forces a separation.
John makes this clear with the image of the threshing floor. "His winnowing fork is in His hand to thoroughly clear His threshing floor." The harvested grain would be thrown into the air. The heavier wheat would fall to the ground, while the worthless chaff would be blown away by the wind. Christ is the one who does the separating. He gathers the wheat, His true people, into His barn, into His kingdom. But the chaff, those who have the outward appearance of being God's people but bear no fruit, He will burn up with unquenchable fire.
Luke concludes this section by summarizing John's ministry. He "proclaimed the gospel to the people." We must not miss this. This fiery message of repentance, judgment, vipers, and the axe is the gospel. It is good news. It is good news because it tells us the truth. It warns us of the danger we are in and points us to the only way of escape. A gospel without repentance and judgment is no gospel at all. It is a cheap, sentimental lie.
"But when Herod the tetrarch was reproved by him because of Herodias, his brother’s wife, and because of all the wicked things which Herod had done, Herod also added this to them all: he locked John up in prison." (Luke 3:19-20)
And here we see the inevitable result of faithful preaching. John did not just preach to the crowds. He confronted the powerful. He called out Herod for his adulterous marriage. John's gospel was not just personal; it was public and political. He applied the law of God to the civil magistrate. And for this, he was imprisoned and eventually beheaded. This is a reminder that the true gospel will always be an offense to the powers that be. A faithful church will always be a church in conflict with a rebellious world. If we are never causing any trouble, it is likely because we are not preaching the same gospel that John did.