en_tn/num/04/17.md

to be removed from among the Levites

This phrase refers to the death of the Kohathites. AT: "to perish from among the Levites" (See: rc://en/ta/man/translate/figs-idiom)

by doing this

This phrase refers to what is said next. (i.e. "they must not go in to see...")

to his work, to his special tasks

These two phrases mean basically the same thing and are combined for emphasis. (See: rc://en/ta/man/translate/figs-parallelism)