Who is the Fool (Proverbs 23:9)

For some, wisdom is not a thing that is desirable and we should be sure to keep our mouths shut because we will be despised.

"Speak not in the ears of a [self-confident] fool, for he will despise the wisdom of your words." Proverbs 23:9, Amplified

Who is the fool? "The fool has said in his heart, 'There is no God.'" (Psalm 14:1, NKJV) "For the foolish person will speak foolishness, and his heart will work iniquity: to practice ungodliness, to utter error against the Lord, to keep the hungry unsatisfied and he will cause the drink of the thirsty to fail." (Isaiah 32:6, NKJV) The fool cares nothing about being corrected for his heart and mind have become so twisted by his own desires and selfishness.

Does this mean that we should not try to correct and witness to these people. No. The Gospel was sent to everyone. The Gospel is for everybody. We need to be wise as serpents, however, and understand to whom we are speaking.