21 Folly brings joy to one who has no sense, but whoever has understanding keeps a straight course.

Read Proverbs 15:21 Using Other Translations

Folly is joy to him that is destitute of wisdom: but a man of understanding walketh uprightly.
Folly is a joy to him who lacks sense, but a man of understanding walks straight ahead.
Foolishness brings joy to those with no sense; a sensible person stays on the right path.