Being a Jew #16 // Kosher I

The LORD spoke to Moses and Aaron, saying to them: Speak to the Israelite people thus: These are the creatures that you may eat from among all the land animals: any animal that has true hoofs, with clefts through the hoofs, and that chews the cud—such you may eat. The following, however, of those that either chew the cud or have true hoofs, you shall not eat: the camel—although it chews the cud, it has no true hoofs: it is unclean for you; the daman—although it chews the cud, it has no true hoofs: it is unclean for you;

There are no other domesticated animals or wild beasts in the world that are permitted to be eaten except the ten species mentioned in the Torah. They are three types of domesticated animals: an ox, a sheep, and a goat, and seven types of wild beasts: a gazelle, a deer, an antelope, an ibex, a chamois, a bison, and a giraffe. [This includes the species] itself and its subspecies, e.g., the wild ox and the buffalo are subspecies of the ox.

All of these ten species and their subspecies chew the cud and have split hoofs. Therefore, a person who recognizes these species need not check neither their mouth nor their feet.

You shall not draw abomination upon yourselves through anything that swarms; you shall not make yourselves unclean therewith and thus become unclean. For I the LORD am your God: you shall sanctify yourselves and be holy, for I am holy. You shall not make yourselves unclean through any swarming thing that moves upon the earth. For I the LORD am He who brought you up from the land of Egypt to be your God: you shall be holy, for I am holy. These are the instructions concerning animals, birds, all living creatures that move in water, and all creatures that swarm on earth, for distinguishing between the unclean and the clean, between the living things that may be eaten and the living things that may not be eaten.

Abraham Ibn Ezra (Spain, d. 1164-1167)​​​​​​​

Do not defile yourselves so as to become soiled and contaminated do not make yourselves ritually impure for it is known that the body which is eaten turns into the flesh of the body who eats it.

Moses Maimonides (1138-1204)

I maintain that the food which is forbidden by the Law is unwholesome. There is nothing among the forbidden kinds of food whose injurious character is doubted, except pork (Lev. 11:7), and fat (ibid. 7:23). But also in these cases the doubt is not justified. For pork contains more moisture than necessary [for human food], and too much of superfluous matter. The principal reason why the Law forbids swine's flesh is to be found in the circumstance that its habits and its food are very dirty and loathsome. It has already been pointed out how emphatically the Law enjoins the removal of the sight of loathsome objects, even in the field and in the camp; how much more objectionable is such a sight in towns. But if it were allowed to eat swine's flesh, the streets and houses would be more dirty than any cesspool, as may be seen at present in the country of the Franks. A saying of our Sages declares: "The mouth of a swine is as dirty as dung itself".

The fat of the intestines makes us full, interrupts our digestion, and produces cold and thick blood; it is more fit for fuel [than for human food]. Blood (Lev. 17:12), and nebelah, i.e., the flesh of an animal that died of itself (Deut. 14:21), are indigestible, and injurious as food; Trefah, an animal in a diseased state (Exod. 22:30), is on the way of becoming a nevalah (an animal that died naturally). The characteristics given in the Law (Lev. xi., and Deut. xiv.) of the permitted animals, viz., chewing the cud and divided hoofs for cattle, and fins and scales for fish, are in themselves neither the cause of the permission when they are present, nor of the prohibition when they are absent; but merely signs by which the recommended species of animals can be discerned from those that are forbidden.

(Leviticus 20:26) "and I have set you apart from the peoples to be Mine": If you are separate from the nations, you are Mine; if not, you are "Nevuchadnezzar's" and his cohorts'. R. Elazar b. Azaryah says: Whence is it derived that a man should not say: I do not desire to wear sha'atnez; I do not desire to eat the flesh of a pig; I do not desire to cohabit with ervah (illicit relations). I do desire it, but what can I do? My Father in heaven has decreed against it! — From "and I have set you apart from the peoples to be unto Me." It is found, then, that he separates from sin because he accepted upon himself the yoke of heaven.

The reason for certain birds being forbidden as food is on account of their cruel nature. It is also possible that the reason for certain animals being forbidden is similar, since no animal that chews the cud and has a parted hoof is a beast of prey, while the rest all devour others. There has also been found a difference in nature between animals fit for food and those which are unfit, as the Sages have mentioned, namely that all milks of animals fit for food curdle, whereas all milks of those unfit for food do not coagulate and cannot ever be made into cheese. Thus they are physically different. It is possible to say on the basis of this difference in their natures that those animals unfit for food harm human beings who eat them.

"Do not eat any detestable thing" This is to say that all forbidden animals are detestable to the pure soul [...] for the forbidden foods are foul, and breed opacity and obtuseness in the soul [...]