For thinking that in their secret sins they were unobserved: For here is a conjunction, meaning “because,” and it goes with they were scattered later in the verse, not with thinking. Translators will find it best to structure the verse after the Good News Translation model. Describing the sins as “secret and unnoticed” (Good News Translation) in the predicate is clearer than speaking of secret sins, or speaking of the people as unobserved, as Revised Standard Version literally translates. Secret sins may refer to the mystery religions (see 14.23 and the note there). See the alternative model in the next paragraph.

Behind a dark curtain of forgetfulness: A dark curtain is not a literal reference to a curtain, but a figure of speech that describes forgetfulness. Forgetfulness is better rendered as “oblivion,” which is being totally unaware of anything. For this line New American Bible has “under the dark veil of oblivion” and New English Bible “beneath a dark pall of oblivion.” The meaning is probably that they thought God did not notice their sins. Because they tried to keep their sins covered by darkness, they were punished by darkness. This could be translated “behind a dark curtain [or, veil] of total secrecy.” The first two lines could be rendered “They thought that God could not have seen or noticed their sins, since they committed them in total secrecy, as if behind a dark curtain.”

They were scattered, terribly alarmed, and appalled by specters: Good News Translation establishes the connection of these lines with the previous lines by “but now.” The word “but” or its equivalent will be helpful to most translators; however, “but now” is idiomatic English. Some translators may have to say “But later” or “Later, however.” Scattered (“confused” in Good News Translation) probably refers to the Egyptians being isolated in their own homes instead of being together in their sinful worship. So we may translate it “all alone.” Specters are ghosts or other terrible mirages. The author is not saying the “ghostly forms” (Good News Translation) actually existed, only that the Egyptians imagined they saw them. A possible conclusion to the verse is “but [now] they were all alone, horribly afraid, and terrified by ghostly forms.”

The Revised Standard Version footnote refers to the reading in most manuscripts, which is “darkened” rather than “scattered.” In Greek the two words are similar. The reading in the Revised Standard Version text is to be preferred. A textual note on the model above could read as follows: “all alone; some manuscripts have in the dark.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on The Wisdom of Solomon. (UBS Helps for Translators). New York: UBS, 2004. For this and other handbooks for translators see here.