strongest support for vegetarianism as a positive ideal anywhere in Torah literature
is in the writings of Rabbi Abraham Isaac Hakohen Kook (1865-1935). Rav Kook was
the first Chief Rabbi of pre-state Israel and a highly respected and beloved Jewish
spiritual leader in the early 20th century. He was a mystical thinker, a forceful
writer, and a great Torah scholar.
Rav Kook was a very prolific
writer who helped inspire many people to move toward spiritual paths. He urged
religious people to become involved in social questions and efforts to improve
the world. His powerful words on vegetarianism are found primarily in A Vision
of Vegetarianism and Peace (edited by Rabbi David Cohen, "The Nazir").
Kook believed that the permission to eat meat was only a temporary concession;
he felt that a God who is merciful to his creatures would not institute an everlasting
law permitting the killing of animals for food.  He stated:
is inconceivable that the Creator who had planned a world of harmony and a perfect
way for man to live should, many thousands of years later, find that this plan
was wrong. 
According to Rav Kook, because
people had sunk to an extremely low level of spirituality (in the time of Noah),
it was necessary that they be given an elevated image of themselves as compared
to animals, and that they concentrate their efforts into first improving relationships
between people. He felt that were people denied permission to eat meat, they might
eat the flesh of human beings due to their inability to control their lust for
flesh. He regarded the permission to slaughter animals for food as a "transitional
tax" or temporary dispensation until a "brighter era" is reached
when people would return to vegetarian diets.  Perhaps to reinforce the idea
that the ideal vegetarian time had not yet arrived, Rav Kook ate a symbolic small
amount of chicken on the Sabbath day.
Rabbi Kook believed that
the permission to eat meat "after all the desire of your soul" was a
concealed reproach and a qualified command.  He stated that a day will come
when people will detest the eating of the flesh of animals because of a moral
loathing, and then it shall be said that "because your soul does not long
to eat meat, you will not eat meat."  Along with permission to eat meat,
Judaism provides many laws and restrictions (the laws of kashrut). Rabbi Kook
believed that the reprimand implied by these regulations is an elaborate apparatus
designed to keep alive a sense of reverence for life, with the aim of eventually
leading people away from their meat-eating habit. 
to Rav Kook, all the laws and restrictions serve to raise the consciousness of
Jews, to get them to think about what they are eating, and to decide if the fare
meets religious requirements. The eating of meat is thus not taken for granted,
and this mandated consideration of what is on the plate can be a first step toward
rejecting meat consumption.
This idea is echoed by Torah commentator
Solomon Efraim Lunchitz, author of K'lee Yakar:
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. 
Kook saw people's craving for meat as a manifestation of negative passions rather
than an inherent need. He and Joseph Albo believed that in the days of the Messiah
people will again be vegetarians.  Rav Kook stated that in the Messianic Epoch,
"the effect of knowledge will spread even to animals...and sacrifices in
the Temple will consist of vegetation, and it will be pleasing to God as in days
of old..."  They based this on the prophecy of Isaiah:
the wolf shall dwell with the lamb,
And the leopard shall lie down with the
And the calf and the young lion and the fatling 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....
shall not hurt nor destroy in all My holy mountain. (Isa. 11:6-9)
Kook believed that the high moral level involved in the vegetarianism of the generations
before Noah, is a virtue of such great value that it cannot be lost forever. 
In the future ideal state, just as at the initial period, people and animals will
not eat flesh.  No one shall hurt or destroy another living creature. People's
lives will no longer be supported at the expense of the lives of animals.
his booklet which summarizes many of Rav Kook's teachings, Joe Green, a recent
Jewish vegetarian writer, concluded that, in adopting the diet that will be used
during the time of the Messiah, Jewish religious ethical vegetarians are pioneers
of the Messianic era; they are leading lives that make the coming of the Messiah
more likely. 
Today most Jews eat meat, but the high ideal
of God, the initial vegetarian dietary law, still stands supreme in the Bible
for Jews and the whole world to see, an ultimate goal toward which all people
Leibowitz, Studies in Deuteronomy, Jerusalem: World Zionist Organization
(3rd edition), 1980, pp. 135-142. Also see Rav Kook`s "Afikim BaNegev in
HaPeles (Berlin), 1903-1904, and "Tallelei Orot" in Tahkemoni (Berne),
2. Quoted by Philip Pick, "The Source of Our Inspiration"
(Jewish Vegetarian Society Paper, London), p. 2.
Nehama Leibowitz, Studies in Bereshit (Genesis) (Jerusalem: World Zionist
Organization (3rd edition), 1976), p. 77.
4. See the discussion
in Joe Green, "Chalutzim of the Messiah-The Religious Vegetarian Concept
as Expounded by Rabbi Kook", p., 2.
5. Ibid, pp. 2,3.
"fragments of Light" in Abraham Issac Kook. edited and translated by
Ben Zion Bokser (New York: Paulist Press, 1978), pp. 316-321.
Quoted by Abraham Chill, The Commandments and Their Rationale, (New York,
1974), p. 400.
8. "Vegetarianism From a Jewish Perspective",
Rabbi Alfred Cohen. Journal of Halacha and Contemporary Society, Vol. 1,
No. 2, (Fall, 1981), p. 45; Arlene Groner, "The Greening of Kashrut - Can
Vegetarianism Become the Ultimate Dietary Law?", The National Jewish Monthly,
1976, p. 13.
9. Olat Rayah, Vol. 1, p. 292. Cited by Cohen,
"Vegetarianism . . . ", p. 45.
10. Rabbi Abraham
Isaac Kook, A Vision of Vegetarianism and Peace.
Rabbi J. H. Hertz, The Pentateuch and Haftorahs (London: Soncino Press,
1958), p. 5.
12. Green, "Chalutzim of the Messiah",