There is a rather complicated sequence of verbal ideas in Good News Translation:

if you refuse
to obey
my command
to serve him.

One of these levels can certainly be eliminated. An alternative might be “if you refuse to serve the king, as I have commanded you….” Another, more drastic option is to reverse the clauses in verse 21 and shorten verse 22 as follows: “If you want to stay in the land that I gave your ancestors, then obey and serve the king of Babylonia. If you do not do so….”

Notice that this verse literally speaks of the voice of the Lord. In this context, of course, it refers to God’s command. Good News Translation restructures this phrase as a first person reference to God (“my command”) for the sake of consistency with the verses before and after it.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on The Shorter Books of the Deuterocanon. (UBS Helps for Translators). New York: UBS, 2006. For this and other handbooks for translators see here.