Leviticus 13:19
And in the place of the boil there be a white rising, or a bright spot, white, and somewhat reddish, and it be shewed to the priest; And in the place of the boil there be a white rising, or a bright spot, white, and somewhat reddish, and it be shewed to the priest;
Leviticus 13:19 belongs to the laws given through Moses in Leviticus 12 to 15 concerning uncleanness, leprosy, cleansing, and sanitation. Those laws of cleansing required visible, physical uncleanness to be removed before the real cleansing of the sanctuary with blood, showing that physical uncleanness and the moral defilement of the sanctuary were distinct. They reflect the need for proper precaution in matters of health and cleanliness. They still stand at the head of all sanitary law, above the sanitary laws understood and enforced by modern physicians, and their enduring superiority proves that divine inspiration guided Moses.
The horrible, loathsome disease of leprosy in the verse is a fitting type, picture, and prefigure of sin as a terrible moral disease embracing every kind of evil thing, including mortal sin. Like leprosy, sin is an inward, universally prevalent, spreading, dreadful disease that destroys its victim, never gets well of itself, cannot be cured by human means, and needs healing. Like leprosy, sin is contagious: the sinner contaminates the very atmosphere, introduces pollution where all before was comparative purity, and by his society leads others to sin, so his influence is more to be feared than the infection of the leper. Cleansing from this sin comes through Christ's blood for those who repent and believe in him.
Jesus Christ's healing of leprosy shows his power to heal. The loathsome leprosy described in the law is still as prevalent in the Holy Land as in scriptural days, and this sameness of the disease bears witness to scriptural truth. The instructions about cleansing are a type for Christians, teaching that God's people must turn from uncleanness and obey the laws of health so they may be clean vessels for the Spirit and ready to receive the latter rain.