Proverbs 10:23

It is as sport to a fool to do mischief: but a man of understanding hath wisdom.

Cross-reference

Proverbs 15:21 repeats the contrast: folly brings joy to the senseless, while understanding leads straight.

Proverbs 26:19 gives the specific example: deceiving then saying 'just joking' — a concrete case of the fool's delight in wickedness.

Proverbs 2:14 describes those who delight in evil — a direct parallel to the fool's pleasure in wicked schemes.

In Proverbs 14:9, fools mock at sin, echoing the fool's delight in wicked schemes from Proverbs 10:23.