34 "You have minds like a snake pit! How do you suppose what you say is worth anything when you are so foul-minded? It's your heart, not the dictionary, that gives meaning to your words. 35 A good person produces good deeds and words season after season. An evil person is a blight on the orchard. 36 Let me tell you something: Every one of these careless words is going to come back to haunt you. There will be a time of Reckoning. Words are powerful; take them seriously.
Matthew Henry's Commentary on Matthew 12:34-36
Commentary on Matthew 12:33-37
(Read Matthew 12:33-37)
Men's language discovers what country they are of, likewise what manner of spirit they are of. The heart is the fountain, words are the streams. A troubled fountain, and a corrupt spring, must send forth muddy and unpleasant streams. Nothing but the salt of grace, cast into the spring, will heal the waters, season the speech, and purify the corrupt communication. An evil man has an evil treasure in his heart, and out of it brings forth evil things. Lusts and corruptions, dwelling and reigning in the heart, are an evil treasure, out of which the sinner brings forth bad words and actions, to dishonour God, and hurt others. Let us keep constant watch over ourselves, that we may speak words agreeable to the Christian character.