Solomon
Proverbs 15:21ESV·traditional attribution

Folly is a joy to him who lacks sense, but a man of understanding walks straight ahead.

Matthew Henry Presbyterian @wholebiblehenry

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.

John Gill Reformed Baptist @doctorgill

Folly is joy to him that is destitute of wisdom,.... Or "that wants a heart" (q), a wise and understanding one; by "folly" is meant sin, for all sin is folly; and that is very pleasing and joyous to a wicked he chooses it and delights in it; instead of being ashamed of it, and sorry for it, he glories in it, and makes his...

Jamieson-Fausset-Brown Reformed @jfbcommentary

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