CHRISTIANITY

Blessed are the merciful.
Matthew 5:7

Behold the birds of the heaven, that they sow not, neither do they reap, nor gather into barns; and your heavenly Father feedeth them.
Matthew 6:26

... as you did it to one of the least of these my brethren, you did it to me.
Matthew 25:40

If you had known what that text means, "I require mercy, not sacrifice", you would not have condemned the innocent.
Matthew 12:7

Are not five sparrows sold for two pence? and not one of them is forgotten in the sight of God.
Luke 12:6

And he said unto them, Which of you shall have an ass or an ox fallen into a well, and will not straightway draw him up on a sabbath day?
Luke 14:5-6

The Passover of the Jews was at hand, and Jesus went up to Jerusalem.  In the temple he found those who were selling oxen and sheep and pigeons, and the money-changers at their business.  And making a whip of cords, he drove them all, with the sheep and oxen, out of the temple; and he poured out the coins of the money-changers and overturned their tables.  And he told those who sold the pigeons, "Take these things away . . . "
John 2:13-17

. . . and he shall wipe away every tear from their eyes; and death shall be no more; neither shall there be mourning, nor crying, nor pain, any more: the first things are passed away.
Revelation 21:4

 . . sacrifices were invented by men to be a pretext for eating flesh.
Clement of Alexandria, Stromata 7.6

. . .  just as divorce according to the Saviour's word was not permitted from the beginning, but on account of the hardness of our heart was a concession of Moses to the human race, so too the eating of flesh was unknown until
the deluge. But after the deluge, like the quails given in the desert to the murmuring people, the poison of flesh-meat was offered to our
teeth. . . .   But once Christ has come in the end of time, and Omega passed into Alpha and turned the end into the beginning, we are no longer allowed divorce, nor are we circumcised, nor do we eat flesh, for the Apostle says, "It is good not to eat flesh, nor to drink wine." 
Jerome (c. 342-420), Adversus Jovianum 1.18

"The moral evils of a flesh diet are not less marked than are the physical ills. Flesh food is injurious to health, and whatever affects the body has a corresponding effect on the mind and the soul. Think of the cruelty to animals that meat eating involves, and its effect on those who inflict and those who behold it. How it destroys the tenderness with which we should regard these creatures of God! . . . "
"The intelligence displayed by many dumb animals approaches so closely to human intelligence that it is a mystery. The animals see and hear and love and fear and suffer. They use their organs far more faithfully than many human beings use theirs. They manifest sympathy and tenderness toward their companions in suffering. Many animals show an affection for those who have charge of them, far superior to the affection shown by some of the human race. They form attachments for man which are not broken without great suffering to them.  What man with a human heart, who has ever cared for domestic animals, could look into their eyes, so full of confidence and affection, and willingly give them over to the butcher's knife? How could he devour their flesh as a sweet morsel?" 
Ellen G. White, The Ministry of Healing (Mountain View, California: Pacific Press Publishing Association, 1942; first published, 1905), pages 315, 316.

If it was God's plan for Christ to be born among animals, why have most Christian theologians denied the value and rights of animals?  Why no theology of the peaceable kingdom? . . . Animals in the stable at Bethlehem were a vision of the peaceable kingdom. Among theology's mysteries, this ought to be the easiest to fathom.
Colman McCarthy, vegetarian and Catholic activist on behalf of nonviolence, The Washington Post, December 25, 1988

Animals, like us, are living souls. They are not things. They are not objects. Neither are they human. Yet they mourn. They love. They dance. They suffer. They know the peaks and chasms of being. . . With us, they share in the gifts of consciousness and life. In a wonderful and inexpressible way, therefore, God is present in all creatures."
Reverend Gary Kowalski, The Souls of Animals, Stillpoint, Walpole, NH, 1991, pg. 111.

Since an animal's natural life is a gift from God, it follows that God's right is violated when the life of his creatures is perverted. . . The de-beaked hen in a battery cage is more than a moral crime, it is a living sign of our failure to recognize the blessing of God in creation.
Reverend Professor Andrew Linzey, Christianity and the Rights of Animals, Crossroad, New York, 1991, pg. 112.

"The choice is between a meat-eating diet that celebrates a fallen world or a vegetarian diet that celebrates new life through the risen Christ. . . The vegetarian meal is a celebration of life in which we permit our fellow creatures to experience the joy of existence that God graciously shared with us and our companions. It beckons us to a gentler, kinder way of life that exemplifies the Christian hope. My prayer is that our daily meals will become spiritual activities that celebrate the wonders and mystery of God and God's creation."
Richard Alan Young, Is God a Vegetarian? Christianity, Vegetarianism, and Animal Rights, Open Court, Chicago, 1999, pp. 163-164.

According to the theological doctrine of animal rights, then, humans are to be the servant species - the species given power, opportunity, and privilege to give themselves, nay sacrifice themselves, for the weaker, suffering creatures.
Reverend Professor Andrew Linzey, Animal Gospel, Westminster John Knox Press, Louisville, KY, 2000, pg. 39.

The decision to live life with respect and concern for all creatures that inhabit the earth is, first of all, an individual choice. But if the human race is to evolve spiritually and morally, that choice must eventually reflect a societal standard. The Kingdom of God promised by the Bible is a kingdom in which humans and non-humans must live in peace with their own kind and with all other species. It is the world promised by the prophets, in which "the wolf also shall dwell with the lamb . . . and the calf and the young lion and the fatling together, and a little child shall lead them." (Isa. 11:6)
Reverend J. R. Hyland, God's Covenant With Animals: A Biblical Basis for the Humane Treatment of All Creatures, Lantern Books, New York, 2000, 68.

To thank God for the fruits of the earth, given to human beings for their sustenance, is a legitimate religious act. But to thank the Lord for providing the flesh of an animal is not legitimate. The eating of flesh is a perversion of God's law, indulged by a fallen human race. And to thank God for providing such food is the modern equivalent of sacrificial religion; it represents a continuing determination to claim God's blessing on the slaughter, and consumption, of His creatures.
Reverend J. R. Hyland, God's Covenant With Animals: A Biblical Basis for the Humane Treatment of All Creatures, Lantern Books, New York, 2000, 102.

Animals are God's creatures, not human property, nor utilities, nor resources, nor commodities, but precious beings in God's sight. ... Christians whose eyes are fixed on the awfulness of crucifixion are in a special position to understand the awfulness of innocent suffering. The Cross of Christ is God's absolute identification with the weak, the powerless, and the vulnerable, but most of all with unprotected, undefended, innocent suffering.
Rev. Andrew Linzey (http://www.jesusveg.com/index2.html)

I believe that flesh eating is an unjust use of another for one's own profit or advantage. It is unjust because it is unnecessary (people do not need to eat animals to survive), cruel, and perpetuates inauthentic relationships among people and between people and the other animals.
Carol J. Adams, "Feeding on Grace: Institutional Violence, Christianity, and Vegetarianism," in Religious Vegetarianism From Hesiod to the Dalai Lama, edited by Kerry S. Walters and Lisa Portness, State University of New York Press, Albany, 2001, pg. 151.

Violence towards humans, violence towards animals, and violence towards the earth is all of one piece -- it is all an endless appropriation of more and more.  Everything and everyone becomes a "resource" that must be appropriated and exploited for human purposes.  Jesus and the early Christians saw that the whole system of violence was madness, and that the answer was not to try to reform it, but simply remove oneself from it entirely.
Keith Akers, The Lost Religion of Jesus: Simple Living and Nonviolence in Early Christianity (New York: Lantern Books, 2000), p. 229.