Numbers 4:18

4:18 “Do not allow the tribe of the families of the Kohathites to be cut off ¹  from among the Levites;

Numbers 8:6

8:6 “Take the Levites from among the Israelites and purify ²  them.

Numbers 16:21

16:21 “Separate yourselves ³  from among this community, ⁴  that I may consume them in an instant.”

[4:18]  ¹ sn The verb is simply the Qal, “do not cut off.” The context calls for a permissive nuance – “do not let them be cut off.” It was a difficult task to be handling the holy things correctly; Moses and Aaron were to see to it that they did it right and did not handle the objects, that is, Moses and Aaron were to safeguard their lives by making certain that proper procedures were followed.

[8:6]  ² tn The verb טָהַר (tahar) means that Moses was “to purify” or “to make ceremonially clean” the Levites so that they could enter the sanctuary and do the work prescribed for them. Whatever is “unclean” is not permitted in the sanctuary at all.

[16:21]  ³ tn The verb is הִבָּדְלוּ (hibbadÿlu), the Niphal imperative of בָּדַל (badal). This is the same word that was just used when Moses reminded the Levites that they had been separated from the community to serve the Lord.

[16:21]  ⁴ sn The group of people siding with Korah is meant, and not the entire community of the people of Israel. They are an assembly of rebels, their “community” consisting in their common plot.