John Gill's Exposition of the Whole Bible
Ecclesiastes 10:3
Yea also, when he that is a fool walketh by the way,.... The king's highway, the common road; as he passeth along the streets, going to any place, or about any business:
his wisdom faileth [him]; or "his heart" p; he appears by his gait, his manner of walking, to want a heart, to be a fool; walking with a froward mouth, winking with his eyes, speaking with his feet, and teaching with his fingers; all which shows the frowardness and folly of his heart, Proverbs 6:12; or he discovers it throughout his conversation, in all the actions of it, in whatsoever business he is concerned, and in all the affairs of life. The Targum is,
"when he walketh in a perplexed way;''
then his wisdom fails him; he does not know which way to take, whether to the right or left: this can never be understood of the highway of holiness, in which men, though fools, shall not err, Isaiah 35:8;
and he saith to everyone [that] he [is] a fool; his folly is manifest to all; he betrays it, by his words and actions, to every man he has to do with; his sins and transgressions, which are his folly, he hides not, they are evident to all; and, as the Targum expresses it,
"all say he is a fool:''
though indeed he himself says this of every other man, that he is a fool; for, according to the Vulgate Latin version, he, being a fool himself, thinks everybody else is so.
p לבו "cor ejus", Pagninus, Montanus, c.