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, and makes a mock at all good men, and everything they say; and therefore what is serious and sacred should not be said to them, since it only becomes the object of their banter and ridicule;

for he will despise the wisdom of thy words; not only the words of doctrine, reproof, and correction, but the "wisdom" of them; or let them be ever so wisely spoken; for if the wisdom of God and his words, the truths of the Gospel, are foolishness with such, and despised by them, then much more the wisdom even of the best of men, and the wisest things they say; yea, when they deliver the wisdom of God in a mystery, the hidden wisdom, the Gospel of Christ, which therefore should be spoken among them that are perfect, 1 Corinthians 1:24.