So Moses numbered them according to the word of the LORD: Moses registered the male Levites just as the LORD instructed him to do. Numbered renders the same Hebrew verb translated “number” in the previous verse (see the comments there). According to the word of the LORD is literally “upon the mouth of the LORD,” which is a figurative expression that means “just as the LORD said.”

As he was commanded: The pronoun he refers to Moses. It may be necessary to make this explicit by saying “as Moses was commanded.” In languages that do not use passive verbs, this clause may be rendered “as the LORD commanded him [or, Moses].”

New International Version avoids some of the repetitiveness in this verse by saying “So Moses counted them as he was commanded by the word of the LORD.” Good News Translation has simply “and Moses did so.” The repetitiveness of the Hebrew text may be a marker of its importance, in this case, to distinguish the census of the Levites from the general census of the other tribes. Thus, if it is possible to preserve the repetition in a natural way, we advise translators to do this, rather than to condense the text as much as Good News Translation has done.

Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .