Question: "Why did John the Baptist refer to the Pharisees as a brood of vipers?"
Answer: John the Baptist condemned the Pharisees and Sadducees as a “brood of vipers” in Matthew 3:7. A “brood of vipers” is a “family of snakes.” Because vipers are venomous, John was essentially calling the religious leaders “deadly sons of serpents.” It’s quite a bold denunciation—and one Jesus repeated to the Pharisees in Matthew 12:34.
The Pharisees and Sadducees were the religious leaders in Israel during the time of John the Baptist and Jesus. The Pharisees were the Law-keepers and promoters of tradition, and the Sadducees comprised the wealthier ruling class. Over the centuries, these well-meaning groups had become corrupt, legalistic, and hypocritical and would eventually be responsible for crucifying the Son of God. They earned their label “brood of vipers,” a sobriquet with deeper meaning than is obvious at first glance.
The viper was seen to be an evil creature. Its venom was deadly, and it was also devious—the viper that bit Paul was hiding in the firewood (Acts 28:3). The Hebrew Scriptures, which the Pharisees knew well, associate the serpent with Satan in Genesis 3. For John to call the Pharisees a “brood of vipers” implies that they bore satanic qualities. This idea is clearly stated by Jesus in John 8:44, where He says the unbelieving Jews “belong to [their] father, the devil.” When John and Jesus called the Pharisees a “brood of vipers,” they were pointing out that these men were deceitful, dangerous, and wicked—deceitful in that they were hypocrites (Matthew 23:15); dangerous in that they were blind leaders of the blind (Matthew 15:14); and wicked in that their hearts were full of murder (John 8:37).
Another fascinating detail is found in Jesus’ use of the epithet “brood of vipers” to describe the Pharisees. In Matthew 23:33, He says, “You brood of vipers, how are you to escape being sentenced to hell?” Farmers, then as now, often burned the stubble of their fields to get the land ready for the next planting season. As the fires neared the vipers’ dens, the snakes would slither away from the flames, but they often did not escape being consumed. Snakes fleeing the fire was a common sight, and Jesus’ words to the Pharisees would likely have called it to their minds. How could they think they would escape the fire of God’s judgment by relying on their own works, which were not at all honest or good? John’s and Jesus’ calling them a brood of vipers was meant to make them aware of their own wickedness and call them to repent.