The psalmist praises God for his power and for his wisdom. Yahweh’s works are great, that is, they are mighty, wonderful; and his thoughts are very deep, that is, profound, mysterious, hard to understand. New Jerusalem Bible translates “subtle.” And instead of thoughts, “plans, designs” may be more appropriate (see the word in 33.10b); God’s plans are beyond human understanding. The expression Thy thoughts are very deep may be rendered in some languages “the things you think, LORD, are difficult for us to understand.”

The psalmist speaks particularly of the inevitable punishment of the wicked; they may prosper for a while, but they cannot escape their eventual destruction.

In verse 6 dull man and stupid are the words used in 49.10b; it is not lack of intelligence the psalmist is talking about, but lack of discernment about God’s power and justice (compare 10.4). Good News Translation‘s “This” points to verse 7. However, it is only the colon after “understand” in the second line that signals the beginning of what “This” refers to. Revised Standard Version has the advantage of keeping this: at the end of verse 6. Biblia Dios Habla Hoy reduces the two lines to one and says “Only fools cannot understand it,” referring back to verse 5. But Revised Standard Version and Good News Translation make verse 6 point forward to verse 7, which seems better.

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 .