The Masoretic text of this verse differs slightly from that of verse 12; instead of Man cannot abide, reading yalin as in verse 12, the Masoretic text here has “man cannot understand” (yabin), which Hebrew Old Testament Text Project prefers. So New Jerusalem Bible “Man does not understand honor” (which makes little, if any, sense in English), and New Jerusalem Bible “In prosperity people lose their good sense,” which is a good thought but hardly seems to be what the psalmist was talking about (see Traduction œcuménique de la Bible, New International Version). But some Hebrew manuscripts have yalin, and so Revised Standard Version, Good News Translation, and others translate verse 20 the same as verse 12.

Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .