What does Proverbs 18:20 mean?
Solomon emphasizes the importance of words in producing a good conscience. If a person's words are kind, gracious, and uplifting, he will benefit. His conscience will not trouble him, and his heart and mind will be at peace. A wise person (Proverbs 1:7; 10:19) is as careful about what he says as he is about what he eats. Good, healthful food serves the stomach well. It does not upset the stomach. Similarly, good, healthful words cause the conscience to be at peace.Among other evils, Jesus referred to unhealthful words as defiling a person. He said: "Do you not see that whatever goes into the mouth passes into the stomach and is expelled? But what comes out of the mouth proceeds from the heart, and this defiles a person. For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. These are what defile a person" (Matthew 15:17–20).