Mark 7:21-22
for from within, from the heart of man proceed wicked designs, adulteries, fornications, murders; thefts,
Luke 6:45
a good man out of the good treasure of his heart produces what is good: and an evil man out of the evil treasure of his heart produces what is evil: for 'tis from the abundance of the heart, that the mouth speaketh.
James 1:26
If a person of an ungovernable tongue pretends to religion, he abuses himself: for his religion is meer illusion.
James 3:5-8
so the tongue is but a small part of the body, yet how grand are its pretensions. a spark of fire! what quantities of timber will it blow into a flame?