מְק֣וֹר חַ֭יִּים שֵׂ֣כֶל בְּעָלָ֑יו וּמוּסַ֖ר אֱוִלִ֣ים אִוֶּֽלֶת׃
Understanding is a fountain of life unto him that hath it; But folly is the chastisement of fools.
Rashi on Proverbs
Intelligence is a fountain of life to one who has it lit. a fountain of life is the intelligence of its possessor. And this is the interpretation of the verse: The intelligence of the one who has it is a fountain of life to him.
Rashi on Proverbs
but the chastisement of the fools is folly But the chastisement of the fools comes to them because of folly. And this is the apparent meaning: Folly is chastisement to the fools.