John Calvin Commentary Deuteronomy 24:8

"Take heed in the plague of leprosy, that thou observe diligently, and do according to all that the priests the Levites shall teach you: as I commanded them, so ye shall observe to do." — Deuteronomy 24:8 (ASV)

Take heed in the plague of leprosy. I am aware of how greatly interpreters differ from each other and how variously they twist what Moses has written about leprosy. Some are too eagerly devoted to allegories. Others think that God, as a prudent Legislator, merely gave a commandment of a sanitary nature so that a contagious disease would not spread among the people.

This notion, however, is very poor and almost meaningless. It is briefly refuted by Moses himself, both when he recounts the history of Miriam’s leprosy and also when he assigns the cause why lepers should be put out of the camp: namely, that they might not defile the camp in which God dwelt, as he ranks them with those who have an issue and those defiled by the dead.

Therefore, I have thought it well, before attempting the full elucidation of the matter, to present two passages by way of preface, from which God’s design may more fully appear. When, in this passage from Deuteronomy, He commands the people to take heed and observe diligently the plague of leprosy, there can be no question that He thus ratifies what He had previously explained at greater length in Leviticus.

First of all, He refers the judgment of the matter to the priests, so that what they pronounce should be firm and unalterable. Secondly, He would have the priests—lest they pronounce rashly and according to their own wishes—follow simply what He prescribed to them. Thus, they are only to be ministers or heralds, while He alone, in His sovereign authority, is to be the Judge.

He confirms the law He imposes with a special example: He had cast out Miriam, the sister of Moses, for a time, so that her uncleanness during her leprosy would not defile the camp.

The view that some take—that He exhorts the people so that, through sin, they would not bring upon themselves the same evil as Miriam—is not to the point. But what I have stated makes excellent sense: namely, that God’s command, by which He prohibited Miriam from entering the camp, was to have the force and weight of a perpetual law, because He thus ordained what He would always have done.