* This.
   The distinction of clean and unclean animals, (see note on Le
   11:2) existed even before the flood, though it probably then
   only related to sacrifices; but at this time we find there
   were very particular laws enacted respecting the diet of the
   people, and the ceremonial uncleanness contracted by touching
   the carcases of unclean animals.  The reasons for the
   enactment of these laws seem to be--1.  As a test of
   obedience, and to teach the Israelites habits of self-denial,
   and the government of their appetites.  2.  To keep them
   distinct from other nations, and consequently from their
   idolatrous usages, by throwing hindrances in the way of their
   social intercourse; for these distinctions were applicable
   both to persons and things.  The Canaanites not only ate the
   animals prohibited by Moses, which we usually eat, but others
   also, among which dogs were one.  Besides, many of those
   declared unclean were sacred among the heathen, and
   sacrificed to their gods.  3.  Because those prohibited were
   innutritive and unwholesome; as the swine, the flesh of which
   being strong and difficult to digest, affords a very gross
   aliment, and produces, especially in hot climates, cutaneous,
   scrophulous, and scorbutic disorders, as the itch, leprosy,
   etc.

  7:37  14:54  15:32  Eze 43:12