Speak not in the ears of a fool: for he will despise the wisdom of thy words.

Wesley's Notes

23:9 Of a fool - Cast not away good counsels upon incorrigible sinners.

Jamieson-Fausset-Brown Bible Commentary

9. (Compare Pr 9:8). "Cast not your pearls before swine" (Mt 7:6).

Matthew Henry's Concise Commentary

23:1-3 God's restraints of the appetite only say, Do thyself no harm. 4,5. Be not of those that will be rich. The things of this world are not happiness and a portion for a soul; those that hold them ever so fast, cannot hold them always, cannot hold them long. 6-8. Do not make thyself burdensome to any, especially those not sincere. When we are called by God to his feast, and to let our souls delight themselves, Isa 25:6; 55:2, we may safely partake of the Bread of life. 9. It is our duty to take all fit occasions to speak of Divine things; but if what a wise man says will not be heard, let him hold his peace. 10,11. The fatherless are taken under God's special protection. He is their Redeemer, who will take their part; and he is mighty, almighty.

Matthew Henry's Whole Bible Commentary

Verse 9

We are here directed not to cast pearls before swine (Mt. 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. There are some that will make a jest of every thing, though it be ever so prudently and pertinently spoken, that will not only despise a wise man's words, but despise even the wisdom of them, that in them which is most improvable for their own edification; they will particularly reproach that, as if it had an ill design upon them, which they must guard against. 2. Those that do so forfeit the benefit of good advice and instruction, and a wise man is not only allowed, but advised, not to speak in the ears of such fools; let them be foolish still, and let not precious breath be thrown away upon them. If what a wise man says in his wisdom will not be heard, let him hold his peace, and try whether the wisdom of that will be regarded.