John Calvin Commentary Numbers 18:5

"And ye shall keep the charge of the sanctuary, and the charge of the altar; that there be wrath no more upon the children of Israel." — Numbers 18:5 (ASV)

And you shall keep the charge. He again exhorts the priests to be diligent in the performance of their office, adding a denunciation of punishment if they failed in zeal and earnestness. Nor does He now threaten them alone, but the whole people; this does not contradict the previous declaration, since the common fault of all by no means lessened theirs.

Indeed, if God punished the innocent people on account of the pollution of the sanctuary, how much heavier a punishment awaited the priests, (antistites), by whose fault the sin was committed, so that they might be justly considered its authors.

Meanwhile, let us learn from this passage how sincerely we ought to conduct ourselves in the service of God, the profanation of which is intolerable to Him.

Moreover, so that the priests might engage in their duties more actively and with greater diligence, He shows that they cannot give way to idleness without base ingratitude, since they reign, in a manner, over the whole tribe of Levi, or, at any rate, they hold supremacy among their brethren. An indirect reproof of their negligence, if they do not faithfully fulfill their duties, is implied when God reminds them that He has generously honored them with the priesthood.

I have appointed your office, as a gift,²⁰¹ i.e., I have gratuitously conferred on you what was otherwise yours by no right. Others read it differently, namely, I have appointed your priesthood as a ministration of gift: but since the meaning amounts to the same thing, and it does not make any difference in essence, we may freely take our choice.

²⁰¹ “Donum posui munus vestrum.” — .” — Lat. “I have given your office “I have given your office unto you as a service of gift.” — a service of gift.” — A. V. The latter part of the sentence is omitted in The latter part of the sentence is omitted in Fr.