Folly is joy to him that is destitute of wisdom: but a man of understanding walketh uprightly.
Folly (is) joy to (him that is) destitute of wisdom - (Proverbs 10:23.) "Folly," i:e., sin.
But a man of understanding walketh uprightly - conformably to the will of God, the true standard of right. The wicked being "destitute" of true "wisdom," have "joy" in (Proverbs 15:15; cf. Job 20:12), and therefore 'walk' in sin, which is crookedness. The godly being men of understanding, have "joy" in uprightness, and therefore 'walk' on in it. They are deeply sorry when they have been temporarily betrayed into sin (2 Corinthians 7:10-11).