JUDAISM and JUDEO/CHRISTIAN

1. God’s original dietary law

And God said: "Behold, I have given you every herb-yielding seed which is upon the face of all the earth, and every tree that has seed-yielding fruit - to you it shall be for food."
Genesis 1:29

God did not permit Adam and his wife to kill a creature to eat its flesh. Only every green herb shall they all eat together.
Rashi’s commentary on Genesis 1:29

You are permitted to use the animals and employ them for work, have dominion over them in order to utilize their services for your subsistence, but must not hold their life cheap nor slaughter them for food. Your natural diet is vegetarian....
Moses Cassuto (1883 -1951) in his commentary From Adam to Noah

Adam was not permitted meat for purposes of eating.
Babylonian Talmud (Sanhedrin 59b)

2. Attitude toward animals

A righteous person regards the life of his or her animal, but the tender mercies of the wicked are cruel.
Proverbs 12:10

The Lord is good to all and His tender mercies are over all His creatures.
Psalms 145:9

The tzaddik (righteous person) acts according to the laws of justice; not only does he act according to these laws with human beings, but also with animals.
The Malbim

Living creatures possess a soul and a certain spiritual superiority which in this respect make them similar to those who possess intellect (people) and they have the power of affecting their welfare and their food and they flee from pain and death.
Nachmanides, commentary on Genesis 1:29

There is no difference between the pain of humans and the pain of other living beings, since the love and tenderness of the mother for the young are not produced by reasoning, but by feeling, and this faculty exists not only in humans but in most living beings.
Maimonides Guide for the Perplexed

For that which befalls the sons of men befalls animals; even one thing befalls them; as the one dies, so dies the other; yes, they all have one breath; so that man has no preeminence above an animal; for all is vanity. All go to one place; all are of the dust. Who knows the spirit of men whether it goes upward; and the spirit of the animal whether it goes downward to the earth?
Ecclesiastes 3:19-21

It is forbidden, according to the law of the Torah, to inflict pain upon any living creature. On the contrary, it is our duty to relieve the pain of any creature, even if it is ownerless or belongs to a non Jew.
Code of Jewish Law

When horses, drawing a cart, come to a rough road or a steep hill, and it is hard for them to draw the cart without help, it is our duty to help them, even when they belong to a non-Jew, because of the precept not to be cruel to animals, lest the owner smite them to force them to draw more than their strength permits.
Code of Jewish Law

It is forbidden to tie the legs of a beast or of a bird in a manner as to cause them pain.
Code of Jewish Law

You shall not muzzle the ox when he threshes out the corn.
Deuteronomy 25:4

You shall not plow with an ox and an ass together.
Deuteronomy 22:10

While our teacher Moses was tending the flock of Jethro in the wilderness a kid ran away from him. He ran after the kid until it reached Hasuah. Upon reaching Hasuah, the kid came upon a body of water and began to drink. When Moses reached him he said, "I did not know that you were running because [you were] thirsty. You must be tired." He placed the kid on his shoulder and began to walk. The Holy One, blessed be He, said, "You are compassionate in leading flocks belonging to mortals; I swear you will similarly shepherd my flock, Israel."
Midrash Exodus Rabbah 2:2

As God is merciful, so you also be merciful. As he loves and cares for all His creatures and His children and are related to Him, because He is their Father, so you also love all His creatures as your brethren. Let their joys be your joys, and their sorrows yours. Love them and with every power which God gives you, work for their welfare and benefit, because they are the children of your God, because they are your brothers and sisters.
Rabbi Samson Rafael Hirsch, Horeb, Chapter 72, Section 482.

Here you are faced with God's teaching, which obliges you not only to refrain from inflicting unnecessary pain on any animal, but to help and, when you can, to lessen the pain whenever you see an animal suffering, even through no fault of yours.
Rabbi Samson Rafael Hirsch, Horeb, Chapter 60, Section 416.

There are probably no creatures that require more the protective Divine word against the presumption of man than the animals, which like man have sensations and instincts, but whose body and powers are nevertheless subservient to man. In relation to them man so easily forgets that injured animal muscle twitches just like human muscle, that the maltreated nerves of an animal sicken like human nerves, that the animal being is just as sensitive to cuts, blows, and beating as man. Thus man becomes the torturer of the animal soul.
Rabbi Samson Rafael Hirsch, Horeb, Chapter 60, Section 415.

It seems doubtful from all that has been said whether the Torah would sanction 'factory farming,' which treats animals as machines, with apparent insensitivity to their natural needs and instincts. This is a matter for decision by halachic authorities.
Rabbi Aryeh Carmell, Masterplan: Judaism: its Programs, Meanings, Goals (New York/Jerusalem: Feldheim, 1991), 69.

The current treatment of animals in the livestock trade definitely renders the consumption of meat as halachically unacceptable as the product of illegitimate means.
Rabbi David Rosen, "Vegetarianism: An Orthodox Jewish Perspective", in Rabbis and Vegetarianism: An Evolving Tradition, edited by Roberta Kalechofsky (Micah Publications: Marblehead, Massachusetts, 1995), 53.

3. Messianic times

And the wolf shall dwell with the lamb,
And the leopard shall lie down with the kid;
And the calf and the young lion and the falling together;
And a little child shall lead them
And the cow and the bear shall feed;
Their young ones shall lie down together,
And the lion shall eat straw like the ox . . . .
They shall not hurt nor destroy in all My holy mountain...
Isaiah 11:6-9

The progress of dynamic ideals will not be eternally blocked. Through general, moral and intellectual advancement... shall the latent aspiration of justice for the animal kingdom come out into the open, when the time is ripe.
Rabbi Abraham Isaac Hakohen Kook, A Vision of Vegetarianism and Peace

4. Attitudes toward vegetarianism

The removal of blood which kashrut teaches is one of the most powerful means of making us constantly aware of the concession and compromise which the whole act of eating meat, in reality, is. Again it teaches us reverence for life.
Samuel Dresner, The Jewish Dietary Laws, 29

Apparently the Torah was in principle opposed to the eating of meat. When Noah and his descendants were permitted to eat meat this was a concession conditional on the prohibition of the blood. This prohibition implied respect for the principle of life ("for the blood is the life") and an allusion to the fact that in reality all meat should have been prohibited. This partial prohibition was designed to call to mind the previously total one.
Rabbi Moses Cassutto, quoted by Nehama Leibowitz, Studies in Genesis, 77.

The Torah teaches a lesson in moral conduct, that man shall not eat meat unless he has a special craving for it... and shall eat it only occasionally and sparingly.
B.T. Chulin 84a

Only a scholar of Torah may eat meat, but one who is ignorant of Torah is forbidden to eat meat.
B.T. Sanhedrin 49b

What was the necessity for the entire procedure of ritual slaughter? For the sake of self discipline. It is far more appropriate for man not to eat meat; only if he has a strong desire for meat does the Torah permit it, and even this only after the trouble and inconvenience necessary to satisfy his desire. Perhaps because of the bother and annoyance of the whole procedure, he will be restrained from such a strong and uncontrollable desire for meat.
Rabbi Solomon Efraim Lunchitz, Kli Yakar

Accordingly, the laws of kashrut come to teach us that a Jew's first preference should be a vegetarian meal. If, however, one cannot control a craving for meat, it should be kosher meat, which would serve as a reminder that the animal being eaten is a creature of God, that the death of such a creature cannot be taken lightly, that hunting for sport is forbidden, that we cannot treat any living thing callously, and that we are responsible for what happens to other beings (human or animal) even if we did not personally come into contact with them.
Rabbi Pinchas Peli, Torah Today, Washington, D.C.: B’Nai B’rith Books, 1987, 118.

5. Emphasis on plant foods

For the Lord your God brings you into a good land, a land of brooks of water, of fountains and depths, springing forth in valleys and hills; a land of wheat and barley, of vines and fig trees and pomegranates; a land of olive trees and honey; a land wherein you shall eat bread without scarceness, you shall not lack anything in it... And you shall eat and be satisfied, and bless the Lord your God for the good land which He has given you.
Deuteronomy 8: 7-10

I will give you the rain of your land in its due season, the first rain and the latter rain, that you may gather in your corn, and your wine, and your oil.
Deuteronomy 11:14

I shall return my people from captivity, and they shall build up the waste cities and inhabit them, and they shall plant vineyards and drink the wine from them, and they shall make gardens and eat the fruit from them, and I shall plant them upon their land.
Amos 9:14-15

Build houses and dwell in them, and plant gardens and eat the fruit of them.
Jeremiah 29:5

6. Covenants with animals

"As for me," says the Lord, "behold I establish My Covenant with you and with your seed after you, and with every living creature that is with you, the fowl, the cattle, and every animal of the earth with you; of all that go out of the ark, even every animal of the earth."
Genesis 9:9-10

And in that day will I make a covenant for them with the animals of the field and with the fowls of heaven and with the creeping things of the ground. And I will break the bow and the sword and the battle out of the land and I will make them to lie down safely.
Hosea 2:20

7. Views on Health

You may not rob yourself of your life nor cause your body the slightest injury... Only if the body is healthy is it an efficient instrument for the spirit's activity... Therefore you should avoid everything which might possibly impair your health... And the law asks you to be even more circumspect in avoiding danger to life and limb than in the avoidance of other transgressions.
Rabbi Samson Raphael Hirsch, Horeb, Chapter 62, Section 428.

Since maintaining a healthy and sound body is among the ways of God - for one cannot understand or have any knowledge of the Creator if he is ill - therefore he must avoid that which harms the body and accustom himself to that which is helpful and helps the body become stronger.
Maimonides, Mishneh Torah, Hilchot Deot, 4:1

Limiting our presumption against our own body, God's word calls to us: "Do not commit suicide!" "Do not injure yourself!" "Do not ruin yourself!" "Do not weaken yourself!" "Preserve yourself!"
Rabbi Samson Raphael Hirsch, Horeb, Chapter 62, Section 427

Following the many precedents prescribed in the Code of Jewish Law, we would have little difficulty in arriving at the conclusion that, if indeed eating meat is injurious to one's health, it is not only permissible, but possibly even mandatory that we reduce our ingestion of an unhealthful product to the minimal level.
Rabbi Alfred Cohen, "Vegetarianism From a Jewish Perspective", Journal of Halacha and Contemporary Society, Vol. 1, No. II, (Fall, 1981), 61.

As it is halachically prohibited to harm oneself and as healthy, nutritious vegetarian alternatives are easily available, meat consumption has become halachically unjustifiable.
Rosen, Rabbi David, "Vegetarianism: An Orthodox Jewish Perspective", in Rabbis and Vegetarianism: An Evolving Tradition, edited by Roberta Kalechofsky (Micah Publications: Marblehead, Massachusetts, 1995), 54.)

8. Prophets’ views on sacrifices

For I spoke not unto your fathers, nor commanded them on the day that I brought them out of the land of Egypt, concerning burnt- offerings or sacrifices; but this thing I commanded them, saying, "Obey my voice, and I will be your God, and you shall be my people; and walk in all the ways that I have commanded you, that it may be well unto you.
Jeremiah 7:22 -23

I desire mercy, not sacrifice.
Hosea 6:6

"To what purpose is the multitude of your sacrifices unto Me?" says the Lord. "I am full of the burnt offerings of rams, and the fat of beasts; and I delight not in the blood of bullocks, or of lambs or of he-goats. . . bring no more vain oblations... Your new moon and your appointed feasts my soul hates; ... and when you spread forth your hands, I will hide my eyes from you; yes, when you make many prayers, I will not hear; your hands are full of blood."
Isaiah 1:11-16

I hate, I despise your feasts, and I will take no delight in your solemn assemblies. Though you offer me burnt offerings and your meal offerings, I will not accept them; neither will I regard the peace-offerings of your fat beasts. Take away from me the noise of your song; and let Me not hear the melody of your psalteries. But let justice well up as waters, and righteousness as a mighty stream.
Amos 5:21- 4

He that kills an ox is as if he slew a person.
Isaiah 66:3