The tongue is one of the smallest parts of the body, yet it can do the most damage. In these verses David writes about an experience he had with Doeg, who had a wicked, boastful tongue. David cautions us about two kinds of damaging tongues.
First, beware of a boastful tongue. Doeg was a proud man. In his boastful pride, he told Saul about David, and it cost people's lives. We like to boast because it inflates our ego. But those who boast should boast in the Lord. If we boast in the Lord, we glorify Him.
Second, beware of a sharp tongue. David says of Doeg, "Your tongue devises destruction, like a sharp razor, working deceitfully" (v. 2). He had a lying, sharp tongue. "You love evil more than good, and lying rather than speaking righteousness. You love all devouring words, you deceitful tongue" (w. 3,4). Have you ever been cut by someone's sharp tongue? Or worse, have you ever cut someone with your words? What really hurts is when we cut someone with lies. Lying is a terrible sin. Satan is a liar and a murderer. He wants to use our tongues to spread deceit, not righteousness.
In verse 1 David magnifies the goodness of God: "The goodness of God endures continually." When we boast of the goodness of God, our tongues are medicine that heals, not sharp razors that cut. Our tongues are used to speak righteousness, not to spread lies. They will boast about the Lord, not about ourselves. Let's yield our hearts to God so that our tongues might be used for blessing.
We need to keep our tongues under control. They are capable of causing great damage. Beware of having a boastful or sharp tongue. Be careful that your tongue does not spread lies. And when others slander you, don't reciprocate with your own tongue. Instead, use your tongue to glorify God and to speak of His goodness.
"Why do you boast of evil, you mighty hero? Why do you boast all day long, you who are a disgrace in the eyes of God? You who practice deceit, your tongue plots destruction; it is like a sharpened razor. You love evil rather than good, falsehood rather than speaking the truth. You love every harmful word, you deceitful tongue!"