Leprosy

Biblical leprosy (tsara'at in Hebrew; lepra in Greek) was a broad category of skin diseases governed by detailed priestly diagnosis in Leviticus 13–14. The characteristic OT form was a white spreading condition covering large surfaces of skin, seen in Miriam (Num. 12:10), Naaman (2 Kings 5:1), Gehazi (2 Kings 5:27), and Moses as a temporary sign (Ex. 4:6). The Mosaic law required the leper to be isolated, cry "Unclean! Unclean!" and follow an elaborate purification rite after healing. These regulations made leprosy a powerful symbol of sin's defilement.

Modern scholars recognize that biblical "leprosy" encompassed conditions beyond modern Hansen's disease (Mycobacterium leprae), including psoriasis and other skin disorders. In the NT, Jesus healed lepers as a sign of the messianic age (Matt. 8:2–3; Luke 17:12–14), and his willingness to touch the unclean made these healings also acts of social restoration. He cited his healing of lepers as evidence of his identity to John's disciples (Matt. 11:5).