Leviticus 11:3

Whatsoever parteth the hoof, and is clovenfooted, and cheweth the cud, among the beasts, that shall ye eat.

Leviticus 11:3 gives the test for land animals that may be eaten: the animal must both part the hoof with a divided, cloven foot and chew the cud. It belongs to the law and requirements given through Moses that distinguished animals permitted and fit for food, or clean, from unclean meats unfit for food. That distinction was part of the health principles and sanitary laws taught to Israel, including careful restrictions on Israel's use of animal food in Canaan.

The restrictions forbade swine's flesh and certain other animals because they were not the best articles of food and were hurtful to health, with flesh that could pollute and fill the blood with impurities and shorten life. They were given to preserve the life and health of God's people, keeping their blood pure and their minds and bodies able to function through simple, healthful food. Swine's flesh was expressly prohibited because it would fill the system with humors and in that warm climate often produced leprosy, with an influence far more injurious there than in a colder climate, and swine were never designed to be eaten under any circumstances.

Swine were useful as scavengers permitted to run free to devour decaying substances that would poison the atmosphere, which preserved health. God specified the animals least objectionable for food, but even the permitted meats were still not the food provided as best for Israel; choosing flesh rather than the appointed diet brought loss and kept the people from reaching God's ideal character and fulfilling His purpose. If Israel had submitted to these prohibitions, God would have removed everything injurious to health and suffered no sickness to be among them.

The verse is relevant to the food Daniel and his companions refused, since they would not eat meats classed as unclean in order to preserve health and clear minds for God's service, and Daniel remained faithful to these requirements despite the risk of losing the king's favor, his position, and even his life. The Pharisees distorted these restrictions by adding traditions, extreme rules, and minute regulations, such as straining all drinking water to remove even the smallest insect that might be classed as unclean, turning the rules into an unreasonable burden that kept people anxiously focused on distinguishing clean from unclean.