And the Levites purified themselves from sin, and washed their clothes: Here the Levites carry out the instructions given in verse 7 (see the comments there). The Hebrew verb rendered purified themselves from sin comes from the same root as the word translated “expiation” in verse 7. Rashbam, the medieval commentator, notes that this verb means “to become pure using the water of purification.” However, the Hebrew word for “water” in verse 7 is not repeated here. So we believe Contemporary English Version follows verse 7 too closely here by saying “sprinkled themselves with the water of forgiveness.” Even so, it will still be helpful to bring out the connection between verses 7 and 21. As in verse 7, sin in the sense of deliberate moral wrongdoing is not in view here; rather, this verb refers to ritual pollution that renders a person unfit to participate in worship, so a better model for it is “purified themselves” (Good News Translation, New International Version, New Jewish Publication Society’s Tanakh).

And Aaron offered them as a wave offering before the LORD: See verse 11.

And Aaron made atonement for them to cleanse them: For make atonement, see verse 12; for cleanse see verse 7. Good News Translation shows that the two Hebrew verbs here have a ritual, ceremonial sense by combining them as follows: “He also performed the ritual of purification for them.”

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 .