Verses 15-18 contrast wise and foolish people.

“The simple believes everything”: For “simple” see 1.4. This word in Hebrew is singular but may be expressed in the plural. “Believes” means to accept something as true or real. “Everything” renders a phrase meaning “every word” and probably means here that the simple person accepts as true everything he hears. Such a person lacks the maturity to distinguish between what is true and what is false. Bible en français courant says “A naive person believes everything anyone tells him.”

“But the prudent looks where he is going” is literally “but the prudent watches his steps.” Note Good News Translation. This line contrasts the “prudent” (“wise,” “clever”) person with the “simple” (naive) person in line 1. “Watches his steps” is a figure that means to be cautious, alert, or aware, with the sense of being careful not to be misled by untruth. In some languages this line is expressed, for example, “but the clever person keeps an eye on the path” or “if you are smart you sleep with one eye open.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Proverbs. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .