Ecclesiastes 10:3
Yea also, when he that is a fool walketh by the way, his wisdom faileth him, and he saith to every one that he is a fool.
Cross-reference
In Ecclesiastes 10:15, the same theme of foolishness continues: fools’ toil wearies them and they lack basic knowledge, mirroring the public folly described here.
Ecclesiastes 2:14 contrasts the wise with the fool walking in darkness — the same metaphor of a fool's path revealing his lack of understanding.
In Proverbs 13:16, the same contrast: a prudent man acts with knowledge, while a fool displays folly — mirroring the fool's public lack of sense here.
Proverbs 12:23 directly parallels: 'the heart of fools proclaims folly' — the fool cannot hide his foolishness, just as in Ecclesiastes 10:3.
Proverbs 17:28 says a silent fool may be thought wise — contrasting with Ecclesiastes 10:3 where the fool's behavior betrays him.
Proverbs 14:33 says wisdom makes itself known among fools — implying fools reveal their lack of wisdom, consistent with the fool's public folly.
Proverbs 18:2 describes a fool's love of expressing opinion rather than understanding, showing a similar lack of sense that becomes evident in speech.