The following is an excerpt from
The MacArthur New Testament Commentary on Colossians 4.
Let your speech always be with grace, seasoned, as it were, with salt, so that you may know how you should respond to each person. (Colossians 4:6)
Consistency of life must be followed by consistency of speech. Paul is not speaking here of preaching the gospel, but general conversation. Believers’ speech must always be with grace, as was Christ’s (Luke 4:22). There is no place for those things that characterize the unredeemed mouth. Whether undergoing persecution, stress, difficulty, or injustice, whether with your spouse, children, believers, or unbelievers—in all circumstances believers are to make gracious speech a habit. To speak with grace means to say what is spiritual, wholesome, fitting, kind, sensitive, purposeful, complementary, gentle, truthful, loving, and thoughtful. Paul wrote in Ephesians 4:29, “Let no unwholesome word proceed from your mouth, but only such a word as is good for edification according to the need of the moment, that it may give grace to those who hear.”
The speech of the new man must also be seasoned… with salt. It is not only to be gracious, but also to have an effect. Salt can sting when rubbed into a wound (cf. Prov. 27:6). It also prevents corruption. Believers’ speech should act as a purifying influence, rescuing conversation from the filth that so often engulfs it. Salt also adds flavor, and the speech of the new man should add charm and wit to conversation.
Believers must also know how to respond to each person. They must know how to say the right thing at the right time. In Peter’s words, they must be “ready to make a defense to everyone who asks you to give an account for the hope that is in you, yet with gentleness and reverence” (1 Pet. 3:15).
The speech of the new man is vitally important: “If anyone does not stumble in what he says, he is a perfect man, able to bridle the whole body as well” (James 3:2). Unlike the ungodly, who say “Our lips are our own; who is lord over us?” (Ps. 12:4), we as believers should echo the prayer of the psalmist in Psalm 141:3: “Set a guard, O Lord, over my mouth; keep watch over the door of my lips.”