Psalm 109:17-19 — As he loved cursing, so let it come unto him: as he delighted not in blessing, so let it be far from him. As he clothed himself with cursing like as with his garment, so let it come into his bowels like water, and like oil into his bones. Let it be unto him as the garment which covereth him, and for a girdle wherewith he is girded continually.

I have been struck several times recently by passionate comments by people I love on topics that really matter. They each made great points — and diluted their messages by the language they used.
Kurt Vonnegut was perhaps neither a Christian nor a particularly pleasant man but he was capable of wisdom and in his 1990 novel Hocus Pocus he made the point elegantly when he said “Perhaps the only precept taught me by Grandfather Wills that I have honored all my adult life is that profanity and obscenity entitle people who don’t want unpleasant information to close their eyes and ears to you.”
Profanity doesn’t just dilute the message, however. It offends God. And God is even-handed. “Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap. For he that soweth to his flesh shall of the flesh reap corruption; but he that soweth to the Spirit shall of the Spirit reap life everlasting.” (Galatians 6:7-8). The passage from Psalms makes the application — the man who loves to curse will find his curses rebounding on him.
It is remarkable how many times the Bible insists on purity of language — the prophets, the apostles, the gospel writers — Jesus Himself all make it clear. Jesus said “Hear, and understand: Not that which goeth into the mouth defileth a man; but that which cometh out of the mouth, this defileth a man.” (Matthew 15:10-11)
There is a simple reason for the condemnation of profane language and cursing — to use foul language is to smear filth on God’s creation. Remember what God said about His creation, again and again? “And God saw every thing that he had made, and, behold, it was very good. And the evening and the morning were the sixth day.” (Genesis 1:31). It was very good! Not only is foul language demeaning to creation, it denies the truth of the Creator!
Before I became a Christian my language wasn’t always pretty! Since then I have worked on it, and I make so bold as to say the Holy Spirit worked on it more. It is rare now that I use a word I am ashamed of. I don’t find it restricts my ability to get a point across … I’m going to keep asking my friends to “keep it clean”. Will you do the same?