When He had called the multitude to Himself, He said to them, “Hear and understand: Not what goes into the mouth defiles a man; but what comes out of the mouth, this defiles a man.” Matthew 15:10-11 (NKJV)
There is a disease among the bovine species that has a nick name of “Hoof and Mouth Disease.” I do not remember the symptoms, but it does seem like that it is contagious and it ends with the death of the cattle which are affected by it.
There is a sin among the human race that should be called the “Heart and Mouth” evil of mankind. Symptoms of this are words of hatred, evil doings, a vulgar speaking, debaucherous acts which not only defile the person, but others too.
The religious leaders of Jesus’ day had accused His disciples of eating without washing their hands and defiling themselves. Jesus is pointing out to them their neglect, rejection and twisting of Scripture, by reminding them of the matter of their hearts. It is not what enters the body that defiles; it is what comes out of the mouth.
The words we speak reveal our true heart. The words the Pharisees spoke revealed their hearts. The words the disciples spoke revealed their hearts. The words Jesus spoke revealed His heart. The words I speak reveal my heart as well. And the same with all the human race.
Furthermore, Jesus says,
“Do you not yet understand that whatever enters the mouth goes into the stomach and is eliminated? But those things which proceed out of the mouth come from the heart, and they defile a man. For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies. These are the things which defile a man, but to eat with unwashed hands does not defile a man.” Matthew 15:17-20
O Christian, let us guard our hearts; for out of the heart the mouth speaks. What are you speaking today? Life or death?