He did not confine himself to general exhortations and rebukes. He denounced with truly prophetic sharpness and directness. "You brood of vipers!" he cried to the crowd of Pharisees and Sadducees who had come to hear his preaching, more to criticize than to confess and repent. "Who warned you to flee from the wrath to come?"
According to the Evangelist, "the Pharisees and lawyers rejected the will of God for themselves, not having been baptized by John" (Lk 7:30). Thus they did not accept his mission, even declaring him to be possessed (Lk 7:33).
He exposed all the emptiness and uselessness of their petty ritual disputes and casuistry. For this they in turn hated him. But since John had his authority not from them, but from above, he did not flatter them.
He addressed them with the same prophetic severity as he addressed the crowds they despised, demanding that they "bear worthy fruit of repentance."
In their narrow, pedantic arrogance, they considered their share in the kingdom of the Messiah already secure, simply because they were descendants of Abraham. They supposed that his righteousness would be imputed to them.
In their view, only Israel could find favor with God, precisely by virtue of its ancestral character. They thought and taught that the Kingdom of Heaven would be a purely Jewish kingdom, and that all other nations would be excluded from it.
But John mercilessly overthrew this false casuistic construction. "Do not think to say within yourselves, 'We have Abraham as our father.' For I tell you that God is able from these stones to raise up children for Abraham," and to exclude you, his supposed sons, from the Kingdom if you do not repent.
Such preaching could not fail to strike the scribes and Pharisees. They enjoyed universal honor among all, yet this man addressed them with threatening rebuke.
They imagined that he would be before them like a reed shaken by the wind. In reality, he proved to be an unshakable oak. Flattery and fear were as foreign to his great soul as his rough mantle would have been among the soft garments of a king in a palace.
The sharp contrast between John's teaching and the teaching of the rabbis appeared with special force in the answers he gave to his various questioners.
If fire threatened the rabbis themselves, what fate, in their opinion, must have awaited ordinary people? Yet from the prophet's mouth thundered words that not only aroused fear, but also directed men toward a higher morality in outward deeds.
When the people heard John's terrible preaching, that "even now the ax is laid to the root of the trees; every tree that does not bear good fruit is cut down and thrown into the fire," they asked him in trembling, "What then shall we do?"
He answered them: "He who has two tunics, let him give to him who has none; and he who has food, let him do likewise" (Lk 3:9-11).
If they would help the hungry and the naked, and see in this their duty of love for mankind, they would thereby prove the sincerity of their repentance.
John embraced all classes with his human sympathy. Like Christ Himself, he rejected none of them. The publicans, despised by all, from whom the Pharisees withdrew as from the accursed, found consolation and assurance that they too could receive a share in the Kingdom of Heaven.
When the publicans asked him, "Teacher, what shall we do?" he answered them: "Collect no more than what is appointed for you."
Soldiers also asked him, "And what shall we do?" He said to them: "Do violence to no one, accuse no one falsely, and be content with your wages."
If the publicans honestly fulfilled their duty, and if the soldiers did not use their strength to insult others, but remained faithful to their standard and content with their modest position, this would be a sign of their good repentance.
It would be a sign of their fidelity to conscience, which would bring down upon them the blessing of God.
Yet while demanding practical fruits of repentance, John also pointed out that all who repented would receive special help from above in their moral efforts. He declared that the help of the Spirit of God was necessary for complete inner transformation.
"I baptize with water, but One mightier than I is coming, the strap of whose sandals I am not worthy to loose. He will baptize you with the Holy Spirit and fire."
The hardened would undergo baptism by fire. To the contrite would be given the heavenly gift of a higher will, higher power, and higher knowledge of God, as well as higher communion with Him.
Knowing the needs of the time and filled with the spirit of the prophets, he could not forget how the Old Testament prophets proclaimed, as a sign of the Messiah's coming, that Jehovah would "pour out His Spirit on all flesh" (Joel 2:28).
They also proclaimed that He would "pour water on him who is thirsty, and streams on the dry ground," and that "His Spirit would be on the house of Israel" (Isa 44:3; Ezek 39:29).
Therefore he could not doubt that the One toward Whom he was only the heralding voice, the One whose sandals he would have counted it too great an honor even to loosen, would come not only with vengeance, but also with blessing.
For this He would bring with Him the highest life-giving power, namely the power of the Holy Spirit.
Thus, under the influence of John's preaching and the extraordinary rite of baptism performed by him, the expectation of the Messiah proclaimed by the new prophet grew and strengthened more and more in the soul of the people.
And this Messiah finally came. He appeared openly before the people after His long, unknown stay in distant Nazareth.