There are many connections that can be made between the Jewish holiday of Yom Kippur and vegetarianism:
1. On Yom Kippur, Jews pray to the "Living God", the "King Who delights in life," that they should be remembered for life, and inscribed in the "Book of Life" for the New Year. Yet, typical animal-based diets have been linked to heart disease, stroke, several types of cancer, and other chronic degenerative diseases, that shorten the lives of over a million Americans annually.
2. On Yom Kippur, Jews pray to a "compassionate God," who compassionately remembers His creatures for life. Yet, there is little compassion related to modern intensive livestock agriculture (factory farming), which involves the cruel treatment and slaughter of about 10 billion farm animals annually in the United States.
3. On Yom Kippur, Jews pray to God, "Who makes peace," to be inscribed into the "Book of Life, Blessing, and Peace." Yet, animal-centered diets, by requiring vast amounts of land, water, energy, and other resources, help to perpetuate the widespread hunger and poverty that often lead to instability, violence, and war.
4. On Yom Kippur, Jews are told through the words of Isaiah in the morning prophetic reading that the true purpose of fasting on that day is to sensitize them to the needs of the hungry and the oppressed, so that they will work to end oppression and "share thy bread with the hungry." (Isaiah 58:6,7) Yet, 70 percent of the grain produced in the United States is used to fatten up farm animals, while an estimated 20 million of the world's people die annually from lack of adequate food and nearly a billion of the world’s people are chronically malnourished.
5. One of the most important messages of Yom Kippur and the preceding days is the importance of teshuvah, of turning away from sinful ways, from apathy, from a lack of compassion and sensitivity, and returning to Jewish values, ideals, and mitzvot. Vegetarianism involves a significant turn, away from a diet that has many harmful effects to one that is consistent with Jewish mandates to take care of our health, treat animals compassionately, protect the environment, conserve natural resources, help the hungry, and seek and pursue peace.
6. On Yom Kippur, Jews ask for forgiveness for the sin of "casting off responsibility." Vegetarianism is a way to assume responsibility for our health, for animals, for the environment, and for the world's hungry people.
7. Yom Kippur is a time for reflection and soul searching, a time to consider changes in one's way of life, a time to make decisions for improvement, to break negative habits. Hence, it is an excellent time to switch to a diet that has so many personal and societal benefits.
8. The Yom Kippur liturgy has a prayer that includes the statement that "we are God's flock, and God is our shepherd." Since Judaism teaches that people are to imitate God in His acts of compassion and caring, we should be treating God's defenseless creatures in the ways that we want God to treat us.
9. According to the Jewish tradition, our fate is sealed on Yom Kippur for the coming year. But repentance, charity, and prayer can avert a negative decree. However, people have determined the fate of animals before they are born, and there is virtually no possibility of a change in the cruel treatment and early slaughter that awaits them.
10. Yom Kippur is the Day of Atonement, a day of being, in effect, at-one with God. One way to be more at-one with God is by adopting a plant-based diet, and thereby not harming animals, since "God's compassion is over all His works." (Psalm 145:9)
11 The afternoon service for Yom Kippur includes the reading from the book of Jonah, which tells how Jonah was sent to warn the people of Nineveh that they must do teshuvah, change their sinful ways in order to avoid destruction. Today, the whole world is like Nineveh, in need of redemption, and in danger as never before from a variety of environmental threats. In a sense, vegetarians are now playing the role of Jonah, pointing out that a shift away from an intensive animal agriculture that has significant negative effects on the environment and a shift toward vegetarian diets have become global imperatives, necessary to shift humanity from its current perilous path.
12. An important message of the book of Jonah is that God is concerned about the fate of all of the world's people. Vegetarianism is a way to show such concern and hence to imitate God's attributes of caring and compassion, since this diet requires far less land, grain, water, fuel, and other resources, and hence can contribute to a reduction of the widespread hunger that afflicts so much of humanity.
13. The book of Jonah also shows God's concern for animals. It ends with God's statement, "Should I not then spare the great city of Nineveh with more than one hundred and twenty thousand human beings . . . and much cattle?"
14. On Yom Kippur, one of the many sins that we ask forgiveness for is "the sin we committed before Thee in eating and drinking." This can be interpreted in terms of the harm that animal-based diets do with regard to human health, animals, the environment, and hungry people.
15. On Yom Kippur, Jews are forbidden to wear leather shoes. One reason is that it is not considered proper to plead for compassion when one has not shown compassion to the creatures of God, Whose compassion extends to all His works.
16. Rabbi Israel Salanter, one of the most distinguished Orthodox Rabbis of the nineteenth century, failed to appear one Yom Kippur eve in time for the sacred Kol Nidre Prayer. His congregation became concerned, for it was inconceivable that their saintly rabbi would be absent or late on this very holy day. They sent a search party to look for him. After much time, their rabbi was found in a Christian neighbor's barn. On his way to the synagogue, Rabbi Salanter had come upon one of the neighbor's calves, lost and tangled in the brush. Seeing the animal in distress, he freed him and led him home. His act of compassion represented the rabbi's prayers on that Yom Kippur evening.
In summary, a shift to vegetarianism is an important way to do teshuvah, to turn away from a diet that is harmful in many ways to one that is in accord with the many significant teachings and values that Yom Kippur represents.