Ye shall know. My threats are not vain; this ye shall experience and be forced to acknowledge. This commandment is the purpose and threat, as in Malachi 2:1 (where see note). That my covenant might be with Levi; i.
e. that my covenant with Levi might remain firm. The covenant with Levi was the election of that tribe to be the ministers of the sanctuary. There is here a special allusion to the blessing pronounced on Phinehas for his conduct in the matter of Zimri (Numbers 25:12, Numbers 25:13).
This election is called "a covenant," because, while conferring certain privileges, it involved certain duties. The difficulty in this interpretation is that the verb used here (hayah) does not mean "to remain," "to continue," but only "to be, to exist."
Hence many critics take "the commandment" as the subject, translating. "That it (my purpose) may be my covenant with Levi, i.e. that as God observed the covenant made with the tribe of Levi in old time, so for the future this commandment and threat will be as vigorously observed and take the place of the old covenant.
This explanation is too involved and refined to be acceptable. It is easiest to translate, with Henderson and Reinke, "Because my covenant was with Levi," and to understand God as implying that he warned and punished the priests, because he willed that the covenant with Levi should hold good, and he thus desired to have a body of priests who would keep their vows and maintain the true priestly character.
What that character is he procoeds to unfold.