Viper: Figurative
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Matthew 3:7
But when John saw many of the Pharisees and Sadducees coming to his place of baptism, he said to them, “You brood of vipers, who warned you to flee from the coming wrath?
Matthew 23:33
You snakes! You brood of vipers! How will you escape the sentence of hell?
Luke 3:7
Then John said to the crowds coming out to be baptized by him, “You brood of vipers, who warned you to flee from the coming wrath?