This verse presents a strong contrast to the preceding one; in the Septuagint the contrast is even stronger: “The evil are not like this, not at all like this” (this is followed by New Jerusalem Bible). The Hebrew Old Testament Text Project (Hebrew Old Testament Text Project) prefers the Masoretic text (“C” decision).

So refers to the whole description of the righteous in verses 1-3. The translation of “this” as in Good News Translation may cause a problem, since the reader may not realize that it points to the entire preceding clause. The contrast may be rendered more clearly as “But bad people do not succeed at all,” or “But evil people do not do well,” or “But evil people fail in all they do.”

The wicked (same as verse 1) are compared to the worthless chaff, which in the process of winnowing grain was blown away by the wind. After the cut grain stalks were tramped and crushed on the threshing floor, they were pitched into the air by use of a winnowing shovel. The grain fell to the ground and the chaff (or, straw) was blown away. The main point of the comparison is the worthlessness of chaff, which is allowed to be blown away because it is of no value whatever.

The translation of chaff presents no problem in cultures where grains are grown. Elsewhere it is often necessary to use a descriptive phrase which indicates something light and of little value that can be blown by the wind; for example, “dry grass” or “dry leaves.”

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 .