“‘In those days John the Baptist appeared in the wilderness of Judea, proclaiming,‘Repent, for the kingdom of heaven has come near.’This is the one of whom the prophet Isaiah spoke when he said,
‘The voice of one crying out in the wilderness:
‘Prepare the way of the Lord,
make his paths straight.’
Now John wore clothing of camel’s hair with a leather belt around his waist, and his food was locusts and wild honey. Then the people of Jerusalem and all Judea were going out to him, and all the region along the Jordan, and they were baptized by him in the river Jordan, confessing their sins.
But when he saw many Pharisees and Sadducees coming for baptism, he said to them, ‘You brood of vipers! Who warned you to flee from the wrath to come? Bear fruit worthy of repentance. Do not presume to say to yourselves, ‘We have Abraham as our ancestor’; for I tell you, God is able from these stones to raise up children to Abraham. Even now the ax is lying at the root of the trees; every tree therefore that does not bear good fruit is cut down and thrown into the fire. I baptize you with water for repentance, but one who is more powerful than I is coming after me; I am not worthy to carry his sandals. He will baptize you with the Holy Spirit and fire. His winnowing fork is in his hand, and he will clear his threshing floor and will gather his wheat into the granary; but the chaff he will burn with unquenchable fire.’” ~ Matthew 3:1–12
It is fairly obvious that John the Baptist took inspiration from the prophet Isaiah. Isaiah often talked about how, when the messiah comes, social injustices were going to be leveled. Valleys would be filled in. Mountains would be brought down. Imagery like this. Further, it is also obvious that John the Baptist, like Isaiah before him, had an apocalyptic image of God that included what we can only call “wrath.” In other words, in John’s mind, in order for social injustices to be leveled, God was going to intervene with apocalyptic wrath and destruction. This is why, as he so clearly states here in verse 12, the one coming after him (i.e., Jesus) will burn the chaff with “unquenchable fire.” It will be because the wrath of God burns in such a way so as to destroy those who are committing the injustices against God’s people.
Jesus, on the other hand, never really behaves in the same way John expects. This is why, in Luke 7:18–23, we have an account of John sending his disciples to question Jesus about whether he is “the one” or not. To put it simply, John is torn because, on the one hand, he wants to believe Jesus is the chosen one, but on the other, isn’t witnessing the type of behavior expected of such a chosen one. John expects the messiah to come in with guns blazing, but Jesus has a different tactic (and theology, for what it’s worth). We see this most clearly in Luke 4, during Jesus’ first “sermon” in the synagogue in Nazareth. When Jesus reads from Isaiah 61:1–2—the passage about the Day of Jubilee—he omits a key phrase that nearly gets him killed: “the day of vengeance of our God.” Again, in order for the valleys to get filled and the mountains brought low, God’s wrath and vengeance were going to have to be on full display. The people knew this. The “Bible” was clear. Isaiah believed this. John the Baptist believed this. But it was not so for Jesus. This is what confounded John and the people of Nazareth.
This is why it is always important to put things in their proper context. Sure, today’s passage has a destructive tone. An ax chopping down a true. Chaff burning with unquenchable fire. But that’s just how some folks thought of things. The Jews were an oppressed people, but also believed that one day they would be liberated. Fair enough! That was what was promised to them through Abraham. They just didn’t quite understand the “how” of the equation. To our human minds, it only makes sense that our oppressors will have to be utterly destroyed in order for us to be free. But for Jesus, the true messiah, well, he had a different way of going about things. For him, deliverance was coming, the kingdom of God was coming, but it was going to be inaugurated without any such violence and wrath. This is what makes Jesus a truly unique messiah.