Proverbs 23:9 (BSB)

Do not speak to a fool, for he will despise the wisdom of your words.

From Proverbs 23. Also in the ESV.

Commentary on Proverbs 23:9

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Proverbs 23:9: We are here directed not to cast pearls before swine (Mat 7:6) and not to expose things sacred to the contempt and ridicule of profane scoffers. It is our duty to take all fit occasions to speak of divine things; but, 1.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Proverbs 23:9: Speak not in the ears of a fool,.... For it is only beating the air, and speaking to the wind; it is casting pearls before swine, and that which is holy to dogs. By the "fool" is meant a wicked man, one abandoned to sin, and hardened in it; that scoffs at all admonitions and reproofs, that derides the word, and the preachers of it...
• Jamieson-Fausset-Brown (Reformed), Commentary Critical and Explanatory on the Whole Bible on Proverbs 23:9: (Compare Pro 9:8). "Cast not your pearls before swine" (Mat 7:6).
• Keil & Delitzsch (Lutheran), Biblical Commentary on the Old Testament on Proverbs 23:9: Pro 23:9 Another case in which good words are lost: Speak not to the ears of a fool, For he will despise the wisdom of thy words. To speak in the ears of any one, does not mean to whisper to him, to so to speak that it is distinctly perceived. כּסיל, as we have no often explained, is the intellectually heavy and dull, like pinguis and tardus; Arab.