NOTES for Mat 3:4-6
The Gospel image of John the Baptist most of all recalls the early prophets, especially Elijah. And the Savior Himself compares him precisely with Elijah. Historians connect John and his preaching with the Essenes, with the Qumran community, supposing that he began his spiritual path there, on the shore of the Dead Sea.
And indeed, at first glance it may appear that John preaches almost the same thing as the Essenes. But precisely "almost." All Essenes, including members of the Qumran community, were sure of their chosenness. They were sure that the Messiah would come only for their sake. Simply because no one except them had managed to preserve the spiritual and ritual purity necessary for meeting the Messiah. The Essenes did not pity the impure: in any case they were doomed, and there was no point in saving them, not to mention that it was impossible. One could be saved only in a community like Qumran; all the rest were doomed. The Messiah would come in order to lead His own out of this world sunk in evil. The rest were doomed: that same Messiah would burn the world with all its sins and impurity in a cosmic fire. Those He did not take with Him would perish. John, however, speaks of conversion, which opens to the repentant the path into the Kingdom. Yes, people have things from which they must be cleansed, and the cleansing will be harsh, fiery, not easy to pass through. And yet the path into the Messiah's Kingdom is closed to no one.
There are, however, exceptions: the Pharisees and Sadducees, whom John directly calls "offspring of vipers." The point is not that the former, the Pharisees, were spiritual leaders of the religious establishment, while the latter, the Sadducees, were connected with the priesthood and quite possibly even with the Temple elite. The point is that neither group felt any need for repentance, cleansing, or new conversion.
They were ready to perform one more purifying washing, since this mysterious newly appeared prophet insisted on it. After all, he really might turn out to be a man of God, and an extra washing would not hurt in any case. But deep in their hearts they were sure that they were already ready to meet the Messiah, already clean from sin and righteous. This, and nothing else, separated them from Christ coming into the world and from His Kingdom. No washing in itself could help them, for Christ needs our heart, not our washings.