Matthew 3:7

And seeing many of the Pharisees and Sadducees come for the baptism, he said to them; Offspring of vipers, who has warned you to flee from the wrath to come?

Matthew 23:33

Serpents, offspring of vipers! How can you escape the judgment of hell?

Romans 3:13

their throat is an opened tomb, with their tongues they practise deceit, the poison of asps is under their lips.

James 3:8

but the tongue can no man tame; it is a disorderly evil, full of a 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 opened tomb, with their tongues they practise deceit, the poison of asps is under their lips.
James 3:8
but the tongue can no man tame; it is a disorderly evil, full of a deadly poison.