In an era before effective medical treatments, before science, and before evidence-based medicine, it is fascinating to see how the religious concept of ritual states (i.e. "clean" & "unclean"), helped the ancient Israelites to control disease in the population.
If the skin disease was invasive (lit. "deeper than the skin") or potentially infectious (lit. involved open sores "raw flesh"), a person was declared "unclean". "Unclean" people lived in isolation from mainstream society (Lev 13:46).
If the disease was non-invasive the person was quarantined for 7 days then re-examined. If the disease had spread or faded, the person was declared unclean or clean respectively.
If there was no change they were quarantined for a further 7 days and then re-examined again. If after the second examination there had still been no spread or changes the disease was considered chronic and non-dangerous. Consequently, the person was declared "clean".
All "clean" people exiting quarantine had to wash their clothes (Lev 13:6,34).
If someone with invasive or open-sore disease healed, they returned to the priest to be re-examined & reclassified "clean". Conversely, if someone was declared "clean" and their disease developed to become invasive or open-sore disease they had to present themselves to be re-examined and reclassified "unclean".
I'm sure there are plenty of allegorical ways we can interpret Leviticus 13. Especially if we relate the skin diseases to the invasive and infectious nature of sin. But as a medical student I was fascinated looking at and considering the literal consequences of this passage, particularly in terms of the wider health implications it would have had on this ancient civilisation. Interesting...
(original post here)