First, we must notice that the purpose of these laws is not public health and hygiene. Although they deal with a disease (or with a few diseases), never once does the Bible say that they are for the prevention of sickness in others. Their purpose is ritual cleanliness. This is evident in that: 1) there are no instructions to evaluate other infectious diseases, and 2) the priests never try to cure it; they only examine the sick person to identify the disease and, if he is cured, to present the required sacrifices so he can be reintegrated into Israelite worship. If the main purpose of these laws were health, Yahweh would have spoken of many contagious diseases and given instructions on how to heal them.
Why, then, is there so much interest in ritual cleanliness and leprosy, only one kind of sickness? Because if the skin breaks out in leprosy, it appears to be a corpse. That is what will disturb Aaron when his sister Miriam has the disease: “Let her not be as one dead, whose flesh is half eaten away when he comes out of his mother’s womb” (Numbers 12:12). Leprosy and related skin diseases are different from others because they give the appearance of death, and nothing that appears dead will be accepted before the holy Author of life.
Thanks be to God, leprosy and related skin diseases were not necessarily a death sentence. As Leviticus 14 testifies, Yahweh by grace can heal the sick, and those restored to health also can be reintegrated to the community of believers.
While the world that does not know Yahweh may feel an attraction toward death, show it reverence or even try to imitate it in styles of dress, makeup or celebrations, Yahweh’s people celebrate the life that overcame death, the resurrection of our Lord Jesus Christ. He guarantees our victory over death: “For as in Adam all die, so also in Christ shall all be made alive” (1 Corinthians 15:22). Therefore we Christians celebrate the holiness of our Lord Jesus Christ and avoid all appearances of our defeated enemy.