Deuteronomy 24:8,9

Leprosy was disease of so singular a nature, and to be treated so differently from all others, that we cannot hesitate to conclude, what both Jewish and Christian writers indeed have all agreed in; that it had a reference to somewhat of a spiritual allusion. The priest, and not the physician, was to be consulted upon it. All the laws concerning it, were of a religious kind. Seen therefore with an allusion to the sin of the soul, how apt a representation were all the appointments concerning it, which pointed to the atonement by blood, as the only cure. 1 John 1:7. The case of Miriam is very striking in point. See Numbers 12:10.