Matthew 12:34
O vipers' brood, how can you speak what is good when you are evil? For it is from the overflow of the heart that the mouth speaks.
Romans 3:13-14
"Their throats resemble an opened grave; with their tongues they have been talking deceitfully." "The venom of vipers lies hidden behind their lips."
2 Corinthians 11:3
But I am afraid that, as the serpent in his craftiness deceived Eve, so your minds may be led astray from their single-heartedness and their fidelity to Christ.
James 3:6-8
And the tongue is a fire. That world of iniquity, the tongue, is placed within us spotting and soiling our whole nature, and setting the whole round of our lives on fire, being itself set on fire by Gehenna.