Matthew 15:16

14Let them alone: they be blind leaders of the blind. And if the blind lead the blind, both shall fall into the ditch.

15Then answered Peter and said unto him, Declare unto us this parable.

16And Jesus said, Are ye also yet without understanding?

17Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught?

18But those things which proceed out of the mouth come forth from the heart; and they defile the man.