Land animals that are permitted, or kosher, for Jews to consume are identified in the Torah portion of Re'eh by two distinct characteristics (Levit. 11:1-7, Deut. 14: 4-7).

For example, the cow, goat, sheep and gazelle possess both these characteristics and are deemed kosher. The donkey and the horse, on the other hand, which lack both of these  features, are defined as non-kosher animals. The pig, which has split hooves but does not chew its cud, and the camel, which chews its cud but has no split hooves, are non-kosher animals.

Why do these particular  characteristics cause an animal to become kosher?

The Power of Food

The Kabbalah teaches that the physical attributes of an animal reflect the distinct psychological and spiritual qualities of its soul. Another point expounded by the Jewish sages is that the food a person consumes has a profound effect on one's psyche. Therefore, when a person eats the flesh of a particular animal, the "personality" of this animal affects the identity of the human consumer.

The split hooves and the chewing of the cud represent two qualities of the soul of these animals that are crucially necessary for the healthy development of the Jewish character. When the Jew consumes the substance of these animals, he becomes a more "kosher" and refined human being.

Moral Self-Discipline

Cloven hooves - the division existing in the coverings on an animal's feet - are symbolic of the notion that one's movement in life (reflected by the moving legs) is governed by a division between "right" and "left," between right and wrong, between the permissible and the prohibited. A split hoof represents the human capacity to accept that there are things to be embraced and things to be rebuffed.

This process of moral self-discipline is the hallmark of living a healthy psychological and spiritual life. A violin can produce its exquisite music only when its cords are tied, not when they are loose and "free." Similarly, a human being who allows himself to do whatever he wants, whenever he wants, wherever he wants and with whomever he wants, robs himself of the opportunity to experience the inner music of his soul.

Challenge Yourself

The second quality that characterizes a "kosher" human being is that he always chews his cud.

Even after a person "swallows" and integrates into his life certain perspectives, attitudes and feelings, he must never become totally self-assured and smug about them. The spiritual human being needs to continually regurgitate his notions and ideas to be chewed and reflected upon again.

Man must never allow himself to become fully content in his own. Contentment breeds smugness; smugness breeds boredom or arrogance. A person ought always - till his last breath - challenge himself, examine his behavior and refine his character.