Although true leprosy ("HansenŐs disease) undoubtedly was found in Palestine, the term "leprosy" in the Bible could refer to any number of disfiguring, ulcerating skin diseases. These diseases, caused by bacilli or fungi, could be devastatingly infectious, and quarantine was, therefore, the most immediate and practical social response. Becoming a leper thus meant being excluded from normal human relationships and from the privilege of sanctuary. The leper had to wear symbols of mourning and cry out "Unclean, Unclean!" to warn anyone who came near.
The Law of Moses declared that a leper was ceremonially unclean. Detailed descriptions in the book of Leviticus aided the priests in determining whether a person could be "cleansed" of the disease. Being cleansed seems not to have been connected necessarily with being cured-complete cure of the disease was impossible in many of these infections but rather with no longer being in an infectious state. Once it was determined that a person could be cleansed, the Law prescribed the necessary sacrifices and rituals. The family welcomed this ritual, for it provided a public way for the person to return to society. When Jesus healed lepers, he always instructed them to show themselves to the priests in accordance with Levitical Law. He wanted their cleansing to be publicly acknowledged. He did this for the sake of the leper and his family, as well as to obey the Law.