Matthew 15:16

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

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

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.