Although the lists aren’t exhaustive, listings of clean and unclean animals can be found in Leviticus 11 and Deuteronomy 14, and observant Jews even today will avoid food that isn’t kosher (from the Hebrew kashrut – meaning ‘fit’, ‘proper’, or ‘correct’). So, if an animal is said to be clean it is ‘fit’ or ‘proper’ to eat. On the other hand if an animal is unclean something about it is ‘incorrect’, and it shouldn’t be eaten. Over the years some biblical scholars suggested the reason why some foods were clean or unclean concerned health or hygiene. Others suggested some foods were avoided because of their association with worldly religions. However there are problems with both of these suggestions.
It is my opinion that in God’s original plan he wanted to teach man about good and evil through the animal kingdom. For example, in Romans 5 we are told that by one man sin entered the world, and death entered through sin (Romans 5:12). Some Christians believe there was absolutely no death in God’s creation before Adam’s rebellion, but I don’t hold to this tradition. Specifically, Romans 5:12 says only that death was passed onto all men due to Adam’s rebellion. It does not even imply that death was also passed unto the animal kingdom. Some try to use Romans 8:19-23 as an indicator that death didn’t occur in the animal kingdom prior to Adam’s sin, but this is not so. Eternal life is promised only to man, not to rabbits, worms or sparrows (etc.). What is promised in Romans 8 is that creation will be continually renewed. That is, things won’t become extinct. The extinction of many species of animals reminds us of the fact that God is not at present renewing anything in the old creation—only the spirits of those who are his.
Having said this, if death was absolutely foreign to God’s original and perfect creation, how could Adam know what death was, when he was told he would die, if he ate the forbidden fruit? Unless he was able to observe death in the animal kingdom, how could he understand the concept of death? When naming the animals in Genesis 2, it is implied that Adam studied their behavior, because naming anything in the Old Testament had to do with defining it (what it did) or according to one’s expectation of it (cf. Genesis 35:18). Therefore, when Adam named the lion, he knew how the lion acted—it hunted, stalked its prey and destroyed it by taking its life. Once the lion’s prey was alive, but suddenly it was dead. Its life had vanished, leaving its body limp and motionless. Through this and similar experiences, Adam was enabled to understand the meaning of death.
Even before we are told that clean animals were fit for eating and unclean animals were improper to eat (Leviticus 11 & Deuteronomy 14), we find that Noah was expected to understand what God meant by clean and unclean animals (Genesis 7:2, 8). Some believe that animals were not eaten by mankind until after the Flood (Genesis 9:3). If this is true, then whether or not an animal is kosher has less to do with it being edible and more to do with something else, perhaps its behavior. The lists of foods in Leviticus 11 and Deuteronomy 14 show that carnivores are unfit for eating. This has a spiritual connotation, showing mankind should not prey on the weak or defenseless. In fact, later, the Mosaic Law provided for the poor within the community, and for the widow and the orphan.
A method of determining which mammals were kosher depended upon whether or not they “chewed the cud” and “parted the hoof” (Leviticus 11:3). Chewing the cud has to do with eating and digesting, while parting the hoof has to do with walking. In the New Testament we are told that Jesus is the food of Life (John 6:48-51). If we partake of him we will live forever. However, we are unable to eat the Bread of Life, if we don’t understand and believe (John 6:63-64; cf. John 8:43). Chewing the cud is a figure for fully digesting the word of God, implying thinking about it and letting it nourish our souls. The parted hoof has to do with a walk of separation. We are to come out from the world and be separate (2Corinthians 6:17). We need to behave differently from the world in general, and walk as Jesus walked (John 13:15; 1Peter 2:21).
Mixing these things up is not acceptable. For example, the horse chews the cud but doesn’t part the hoof. In other words a person who understands what God wants but doesn’t behave (walk) accordingly is disobedient, and that is unacceptable. The pig parts the hoof but doesn’t chew the cud. This is a picture of the person who behaves correctly for the wrong reasons—perhaps for good personal relations (good for business or reputation etc.). The problem is his heart is not toward God; he doesn’t understand why his behavior needs to be correct. This, also, isn’t acceptable in God’s Kingdom.
The whole creation of God exists to glorify him. It shows us what kind of God we have. He is good and kind. He doesn’t stalk us by waiting for us to show a sign of weakness so he can pounce upon us for the kill—neither should we behave that way toward our neighbor. We are not to be predators. We are called upon to know, understand and live off God – become like him in every way, as a child loves and desires to be like his parent.
 As I said HERE, this current theme about “making sense of the Old Testament God” is based upon the book: Is God a Moral Monster by Paul Copan. These are my thoughts about his book. He may or may not agree with the impression his book has made upon me, but I thoroughly enjoyed reading what Paul wrote and recommend his book to anyone who is looking for a good read concerning defending our faith.