Ephesians 4:29, “Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear.”

William Shakespeare, in his play, King Lear, wrote, “Mind your speech a little, lest it may mar your fortunes.” This statement recognizes the power of our words to harm our future. Our hateful speech, undiscerning words, and remarks delivered at inopportune times can destroy relationships, end careers, and otherwise bring us much pain.

Scripture we should not be surprised recognizes how our words can be used as weapons. The Scriptures warns readers that we can harm ourselves with our words. With that said, the overwhelming emphasis in God’s Word is often on how our words hurt other people. James warns against misuse of the tongue are primarily intended to prevent false teaching from spreading in the Christian community and to keep people from harming others who bear the image of God (James 3:1–12). Paul concurs with James, explaining in Ephesians 4:29 about the need for Christians to stay away from corrupting talk and to speak only edifying words (Eph. 4:29). Putting off our old selves in favor of Christ means putting away vulgarity, hateful speech, mocking of others’ flaws, and other corrupt talk.

Christians must never utter a harmful word. The Greek term translated corrupt in Ephesians 4:29 is used elsewhere to describe spoiled fruit, rotten fish, and anything else that is worn out and useless. Words with such corruption bring decay to the bonds of fellowship in the church, undermining the effectiveness of the covenant community. If even our idle words will be brought into judgment, how much more will speech designed purposefully to hurt other people impact our assessments and rewards on that last day (Matt. 12:33–37)?

Paul’s point does not mean hard words are never appropriate. After all, sometimes only a hard conversation will turn other people from their sin, thereby edifying them in the long haul (Jude 22–23). Ultimately, the standard for acceptable speech is that which edifies the body of Christ (Eph. 4:29). Our words are to help provide what is lacking in other people, to give them encouragement that will advance their spiritual growth. Jesus spoke these kinds of gracious words (Luke 4:16–22), and we who are His disciples can do no less.

Words spoken to us at just the right time stay with us for the rest of our lives, as do words of malice. If the words of others have this impact on us, then we can be sure that what we say has the same kind of effect on others. Christians should strive to speak only that which will build others up in their faith, which requires Spirit-given discernment regarding what we are to say and when we are to say it.

The renewed person speaks for the sake of personal witness without any words that harm. We are told to put off all unwholesome speech (Eph. 4:29). The word “unwholesome” (Greek sapros) means “rotten” or “putrid” and generally refers to profanity or obscenity. Paul says, literally, “all bad speech do not let journey out of your mouth.” What interesting and instructive language! Bad language begins a journey of decay when it comes out of your mouth, reverberating with effect upon the lives of others. Elsewhere Paul writes that we should “shun profane and vain babblings: for they will increase unto more ungodliness”—they start a journey leading to a destination less godly than where we started (2 Tim. 2:16 KJV). How different is the apostolic instruction from our common and willing misunderstanding of grace; that is, the attitude that says, “Let me show you how well I understand grace; I can use coarse humor and profane language without feeling guilty.” The pervasiveness of profanity in our entertainments and associations has largely desensitized our ears to the apostle’s command, but this wouldn’t surprise him. Paul was in a culture where filthy speech and entertainments were incorporated even into religious practices. He knew how countercultural pure speech was, and perhaps that is why he insisted so upon it, for it is a powerful witness.

We should not think that God is just a persnickety and prudish old grandmother who gasps and frowns about the syllables that come out of our mouths. How strange it would be to think that God is up in heaven concerned to see if our lips, tongues, and larynxes pump out any puffs of air that offend him. It is not the words themselves but rather their journey that more concerns God.

Rotten speech in a very real way spoils the world that we can and do perceive. Similar to the way we can get up in the morning with a groan that seems to make the whole day rotten to us, our rotten expression (critical, dark, and unkind comments) can make putrid our world and the world of those who live with us. God has a more glorious plan for our lives, and our tongues and graciously seeks to preserve the beauty of our world by teaching us to guard our speech.

The concern for our tongues is not limited, however, to the effect of our words on us, but extends to the effects of those words on others. The positive command that corresponds to not using rotten speech (that which is ruinous) is: “Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen” (Eph. 4:29). This imperative is far broader than we may expect or like. Christians are not allowed to say whatever we desire simply by rationalizing that we do not cuss or become coarse. We are not even allowed to fall back upon some category of neutrality in rationalizing what we say, as in “It doesn’t hurt anyone, so it’s all right to say.” The apostle’s standard is that if it does not build up and benefit, then it is not worthy of being said.

With these edifying qualifications, the apostle shows the true colors of his concern. Yes, we are to be concerned for what we say and think and do because of how such matters affect us; and indeed the apostle has graciously lifted our heads to see the grace toward us that motivates such imperatives. But now grace is driven outward toward others, and we are made to understand that what we say is a form of witness. Our words are an instrument of God’s grace toward others by which his own nature is known and shared. The apostle says we are to speak to “give grace to the hearers” (Eph. 4:29d). Thus we are to speak only what builds up and benefits others because our lives are not our own but are meant to show forth the One who indwells us through the Holy Spirit.