On the website “The Straight Dope” someone asks why he starts to cough whenever he cleans his ears with a Q-Tip. The answer: The nerves of the ear and the throat are branches of a single large nerve, the vagus, in the head. In other words, it’s all connected. When you tinker with one, the other one feels it.
But the things that come out of the mouth come from the heart, and these things defile a person.
Matthew 15:18 NET
In the spiritual physionomy, the heart nerve goes straight to the mouth, so much so that the two are used synonymously (Proverbs 15:28; Ecclesiastes 5:2). And, generally, since the heart is evil, what comes from the mouth is evil as well.
Offspring of vipers! How are you able to say anything good, since you are evil? For the mouth speaks from what fills the heart.
When we accept the word of Christ, close to us, things change: “For with the heart one believes and thus has righteousness and with the mouth one confesses and thus has salvation” (Romans 10:10).