Matthew Henry and continuators on Proverbs 15:4

4 A wholesome tongue is a tree of life: but perverseness therein is a breach in the spirit.

Note, 1. A good tongue is healing, healing to wounded consciences by comforting them, to sin-sick souls by convincing them, to peace and love when it is broken by accommodating differences, compromising matters in variance, and reconciling parties at variance; this is the healing of the tongue, which is a tree of life, the leaves of which have a sanative virtue, Rev. xxii. 2. He that knows how to discourse will make the place he lives in a paradise. 2. An evil tongue is wounding (perverseness, passion, falsehood, and filthiness there, are a breach in the spirit); it wounds the conscience of the evil speaker, and occasions either guilt or grief to the hearers, and both are to be reckoned breaches in the spirit. Hard words indeed break no bones, but many a heart has been broken by them.