# You offspring of vipers, who

"You evil poisonous snakes! Who" or "You are evil like poisonous snakes! Who" 

# who warned you to flee from the wrath that is coming?

John rebukes the Pharisees and Sadducees. Alternate translation: "you cannot flee from God's coming punishment like this." or "do not think that you can flee from God's wrath just because I baptize you."

# flee from the wrath that is coming

"run away from the punishment that is coming" or "escape because God is about to punish you"