Proverbs 15:23 A man hath joy by the answer of his mouth; and a word spoken in due season, how good it is.
The conditional promise is: if you answer wisely with your mouth, then you will have joy. There are several promises in Proverbs related to the use of the mouth, tongue, and lips. The words you use and how and when you speak them bring good results when spoken wisely. Words have the power to bring you and others closer to life or to death, that is, you get more of God or more of sin. Here the promise is joy for the speaker, and that would also include others who hear you. And it is blessedly good when spoken at the right time.
Believing this promise of joy and good motivates us to think before opening the mouth in order to speak wise and loving words at the appropriate times. Obviously, cursing, swearing, lying, deceiving, yelling, gossiping words, and using harsh, mean, nasty, critical, and demeaning words are sinful and produce death. And usually, using sweet, kind, tender, loving, warm, encouraging, truthful, and uplifting words tend to produce life in the speaker and the hearer.
But a “word spoken in due season” means using the appropriate words and tones of voice at the right time. For instance, a kind, approving, tender, sympathetic tone is not appropriate when reprimanding a sin. And by the same token, a harsh disapproving, judgmental tone is not appropriate for the repentant sinner who is already genuinely sorry for his sinful behavior. The most fitting word of Law to the smug, or of Gospel to the penitent, is a word “in due season.” This is “how good.”
Words have power to bring joy or bitterness. Ask the Lord for wisdom to know how to answer with the appropriate word and tone. He promises joy and good.