You shall not utter a false report is literally “You [singular] shall not lift up a report of emptiness.” It is quite similar to the commandment in 20.7 regarding “lifting up” the name of Yahweh in “emptiness.” Here, however, it concerns a false report rather than the name. This means “you shall not repeat” (New American Bible) or “spread a baseless rumour” (Revised English Bible). The rest of the verse seems to place such “rumors” in a lawsuit setting. In some languages an indirect object or goal will be necessary for the verb phrase utter a false report; for example, “Don’t spread harmful [or, baseless] rumors about other people” or “Don’t tell stories about other people that are untrue.”

You shall not join hands with a wicked man is literally “Do not put your hand with a guilty [person].” The rest of the verse clarifies what this means: to be a malicious witness, literally “to be a witness of violence.” The idea of “joining hands” means to “assist” (Translator’s Old Testament) or “lend support to” (New Jerusalem Bible), so Good News Translation makes it clear: “do not help a guilty man by giving false testimony.” Contemporary English Version has “Don’t … help a criminal by giving false evidence.” Translators are advised to follow this interpretation. New American Bible understands this malicious witness to be directed against a third party, which is possible: “Do not join the wicked in putting your hand, as an unjust witness, upon anyone.” The words “upon anyone,” however, are not in the text.

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .