“The mouth of the righteous is a fountain of life”: “The mouth” is a poetic use of one of the organs of speech and refers to the words or thoughts spoken by “the righteous”, that is, a good, honest person. “Fountain of life” is similar to “tree of life” used in 3.18. See there for comments. The expression is used in Psa 36.9 (Hebrew verse 10), where it refers to God as being the source or creator of all life. In 16.22 Wisdom is a “fountain of life”. In this verse the expression refers to the words of the righteous, perhaps because such people are identified with the wise and with wisdom. In translation “a fountain of life” must often be expressed as a simile; for example, “. . . are like a fountain that gives life.” “Fountain” renders a word that is also applied to a well dug by people or to a naturally occurring spring.

“But the mouth of the wicked conceals violence”: See verse 6. “The mouth of the wicked” parallels and contrasts with the mouth of the righteous. The contrast here, as in verse 6, is between the words of good people, which are compared to a life-giving fountain, and the evil that hides in the words or thoughts of the wicked. We may translate, for example, “The words of good people are like a spring that gives life, but the words of the wicked hide the harm they will do.”

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 .