Context: John the Baptist, comparing his voice in the desert and his prophecy of the advent of the Lord with those of Isaiah, is preaching in the wilderness of Judea. He calls on the people to repent, declares that "the kingdom of heaven is at hand," and exhorts his hearers to prepare the road for the Lord. From Jerusalem, Judea, and the area of the Jordan, the people come to him, confess their sins, and are baptized in the river. When John sees among the crowd Pharisees and Sadducees, strict, conservative, and proud followers of the law, he likens them to snakes that flee a burning field and warns them against their false security:
But when he saw many of the Pharisees and Sadducees come to his baptism, he said unto them, O generation of vipers, who hath warned you to flee from the wrath to come?