Proverbs 12:18 (BSB)

Speaking rashly is like a piercing sword, but the tongue of the wise brings healing.

From Proverbs 12. Also in the ESV.

Commentary on Proverbs 12:18

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Proverbs 12:18: The tongue is death or life, poison or medicine, as it is used. 1. There are words that are cutting and killing, that are like the piercings of a sword. Opprobrious words grieve the spirits of those to whom they are spoken, and cut them to the heart. Slanders, like a sword, wound the reputation of those of whom they are uttered, and perhaps incurably.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Proverbs 12:18: There is that speaketh like the piercings of a sword,.... Whose words are like sharp swords, cutting, wounding, dividing, killing; see Psa 57:4; such are the words of false witnesses, who by their false testimonies and perjuries are as guilty of the murder of men as cutthroats; such are the words of slanderers, backbiters, and talebearers, who grieve the innocent, wound their characters, destroy their...
• Jamieson-Fausset-Brown (Reformed), Commentary Critical and Explanatory on the Whole Bible on Proverbs 12:18: speaketh--literally, "speaketh hastily," or indiscreetly (Psa 106:33), as an angry man retorts harsh and provoking invectives. tongue . . . health--by soothing and gentle language.
• Geneva Bible Notes (Reformed), Geneva Bible Study Notes on Proverbs 12:18: There is that speaketh like the piercings of a sword: but the tongue of the wise [is] health. (i) Which seek nothing more then to provoke others to anger.