Verses 20-21 are one long sentence. Many translators will wish to divide this long sentence into two or more shorter ones (see Good News Translation).

For if thou didst punish with such great care and indulgence the enemies of thy servants and those deserving of death: The connector For may be omitted. The big problem in these two lines is the meaning of the noun translated indulgence. It is not a common word, and although most translations have “indulgence” or something like it, this is little more than a guess that is based on one meaning of the word, which is “release, discharge, divorce.” This word is also a technical term in music, referring to the smallest detectable interval between two tones. This leads us to think that the meaning, “careful investigation,” is the proper one here (given in the appendix of Liddell and Scott’s Greek lexicon). It fits in with great care (that is, “attention”) in these lines, and with “strictness” (that is, “strict examination”) in verse 21a. The idea is not that God punished people indulgently (that is, mercifully), but that he carefully measured out his punishment on them (compare 11.20). So translators may render the first line as “You were very careful to punish them just enough, but not too much.” As in verse 7, thy servants may be translated “your children” or “your people.”

Granting them time and opportunity to give up their wickedness: Compare verses 2 and 10.

A possible approach to this verse is:

• The enemies of your children [or, servants] deserved to die, yet you were very careful to punish them just enough, but not too much. You gave them every opportunity [or, lots of time] to repent of their sins.

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.