Folly is joy to him that is destitute of wisdom: but a man of understanding walketh uprightly.

King James Translators' Notes

destitute...: Heb. void of heart

Jamieson-Fausset-Brown Bible Commentary

21. walketh uprightly-and so finds his joy (Pr 3:6; 10:23).

Matthew Henry's Concise Commentary

15:16,17. Believers often have enough when worldly eyes see little; the Lord is with them, without the cares, troubles, and temptations which are with the wealth of the wicked. 18. He that is slow to anger, not only prevents strife, but appeases it, if kindled. 19. Those who have no heart to their work, pretend that they cannot do their work without hardship and danger. And thus many live always in doubt about their state, because always in neglect of some duty. 20. Those who treat an aged mother or a father with contempt or neglect, show their own folly. 21. Such as are truly wise, study that their thoughts, words, and actions should be regular, sincere, and holy. 22. If men will not take time and pains to deliberate, they are not likely to bring any thing to pass. 23. Wisdom is needed to suit our discourse to the occasions. 24. A good man sets his affections on things above; his way leads directly thither.

Matthew Henry's Whole Bible Commentary

Verse 21

Note, 1. It is the character of a wicked man that he takes pleasure in sin; he has an appetite to the bait, and swallows it greedily, and has no dread of the hook, nor feels from it when he has swallowed it: Folly is joy to him; the folly of others is so, and his own much more. He sins, not only without regret, but with delight, not only repents not of it, but makes his boast of it. This is a certain sign of one that is graceless. 2. It is the character of a wise and good man that he makes conscience of his duty. A fool lives at large, walks at all adventures, by no rule, acts with no sincerity or steadiness; but a man of understanding, the eyes of whose understanding are enlightened by the Spirit (and those that have not a good understanding have no understanding), walks uprightly, lives a sober, orderly, regular life, and studies in every thing to conform himself to the will of God; and this is a constant pleasure and joy to him. But what foolishness remains in him, or proceeds from him at any time, is a grief to him, and he is ashamed of it. By these characters we may try ourselves.