Matthew 15:11, 17-19

not that which goeth into the mouth defileth a man; but that which cometh out of the mouth, this defileth a man.

Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught? But those things which proceed out of the mouth come forth from the heart; and they defile the man. For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies