G2191 — echidna
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
echidna — pronounced ekh'-id-nah
of uncertain origin; an adder or other poisonous snake (literally or figuratively):--viper.
4 occurrences in the KJV.
Matthew 3:7
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?
Matthew 12:34
O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
Luke 3:7
Then said he to the multitude that came forth to be baptized of him, O generation of vipers, who hath warned you to flee from the wrath to come?
Acts 28:3
And when Paul had gathered a bundle of sticks, and laid them on the fire, there came a viper out of the heat, and fastened on his hand.