Look for the Hebrew root kuf-reish-bet — which has the general sense of “draw near” and/or “sacrifice” — in this portion. Everett Fox, in a commentary section of his Five Books of Moses, notes that chapters 15-18 of Bamidbar/Numbers are “meaningfully linked together by variations on” this root.
The thread of meaning runs from “bringing near-offerings near,” to God “declaring [Moshe and Ahron] near” to him, to the fact that he has “brought-near” the Levites in terms of their duties, to Korach and his band being asked to “bring-near” the incense, whose fire-pans later become holy because they were “brought-near,” and finally, to the repeated warning to outsiders not to “come-near” the sancta. At issue is what Buber calls “authorized” and “unauthorized nearing,” which is mentioned frequently in Leviticus but is used in the present text with the full artistic resources at the narrator’s command. Viewed in this light, order is restored to the blurring of lines threatened by Korah.