Proverbs 15:4

A wholesome tongue [is] a tree of life
A tongue that delivers out salutary instructions, wholesome advice and counsel; a "healing tongue" ^F23, as it may be rendered, which pacifies contending parties, and heals the divisions between them; to have the benefit of such a man's company and conversation is like being in paradise. Such is the tongue of a Gospel minister, which delivers out the wholesome words of our Lord Jesus Christ; sound speech and doctrines, which cannot be condemned; healing truths to wounded consciences, such as peace, pardon, righteousness, and atonement by the blood of Christ. These are the means of quickening dead sinners, reviving and comforting distressed ones, and show the way of eternal life unto them; but perverseness therein [is] a breach in the spirit;
impure, unchaste, unsavoury, and corrupt language, does mischief to the spirits of men; evil communications corrupt the heart and manners, defile the soul and the conversation; these and unsound doctrines eat as a canker; and as they make the heart of God's people sad, whom he would not have made sad; so they bring distress and despair into the spirits of others, and make sad wounds and breaches there, which are never healed, and that both in the spirits of speakers and hearers; for damnable heresies bring swift destruction on the propagators of them, and them that receive them.