Matthew 3:7

But when he saw many of the Pharisees and Sadducees coming to his immersion, he said to them: Generation of vipers, who has warned you to flee from the coining wrath?

Matthew 23:33

Serpents, generation of vipers, how can you escape the condemnation of hell?

Romans 3:13

their throat is an open sepulcher; with their tongues they have used deceit; the poison of asps is under their lips;

James 3:8

but the tongue no man can tame; it is an unruly evil; it is full of deadly poison.

Treasury of Scripture Knowledge

Summary

Their poison is like the poison of a serpent: they are like the deaf adder that stoppeth her ear;

Bible References

Poison

Romans 3:13
their throat is an open sepulcher; with their tongues they have used deceit; the poison of asps is under their lips;
James 3:8
but the tongue no man can tame; it is an unruly evil; it is full of deadly poison.