Romans 3:13
[Psa. 5:9 says], "Their throats are like open graves [i.e., they are foul-mouthed]. They have spoken deceitfully." [Psa. 90:3 says], "There is snake venom under their lips [i.e., their words are deadly]."
Matthew 12:34-35
You children of snakes! Since you are evil, how do you expect to speak good things? For the mouth speaks what the heart is filled with.
Matthew 23:27-28
"It is too bad for you hypocritical experts in the law of Moses and [you] Pharisees! For you are like white-washed tombs, used for burial [sites], which appear beautiful on the outside, but on the inside are full of the bones and decaying flesh of dead people.
Romans 3:4
But let God be truthful, [even if] everyone [else] is a liar. For it is written [Psa. 51:4], "[God], you should be proven right when you speak, and win [your case] when put on trial."
James 3:5-8
So, the tongue is a small part [of the body], yet it boasts of great accomplishments. Look at how large a forest is burned up by even a tiny spark.