There are many connections between vegetarianism and the Jewish holiday of Tisha B'Av:

1. Tisha B'Av (the 9th day of the month of Av) commemorates the destruction of the first and second Temples in Jerusalem. Today the entire world is threatened by destruction by a variety of environmental threats, and modern intensive livestock agriculture is a major factor behind most of these environmental threats.
2. In Megilat Eichah (lamentations), which is read on Tisha B'Av, the prophet Jeremiah warned the Jewish people of the need to change their unjust ways in order to avoid the destruction of Jerusalem. In 1992, over 1,700 of the world's most outstanding scientists signed a "World Scientists Warning to Humanity", stating that 'human beings and the natural world are on a collision course", and that "a great change in our stewardship of the earth and the life on it is required, if vast human misery is to be avoided and our global home on this planet is not to be irretrievably mutilated." Vegetarians join in this warning, and add that a switch toward vegetarianism is an essential part of the "great change" that is required.
3. On Tisha B'Av, Jews fast to express their sadness over the destruction of the two Temples and to awaken us to how hungry people feel. So severe are the effects of starvation that the Book of Lamentations (4:10) states that "More fortunate were the victims of the sword than the victims of famine, for they pine away stricken, lacking the fruits of the field.". Yet, today over 70% of the grain grown in the United States is fed to animals destined for slaughter, as an estimated 20 million people worldwide die annually because of hunger and its effects.
4. During the period from Rosh Chodesh Av to Tisha B'Av known as the "nine days", Jews do not eat meat or fowl, except on the Sabbath day. After the destruction of the second Temple, some sages argued that Jews should no longer eat meat, as a sign of sorrow. However, it was felt that the Jewish people would not be able to obey such a decree. It was also believed then that meat was necessary for proper nutrition. Hence, a compromise was reached in terms of Jews not eating meat in the period immediately before Tisha B'Av.
5. The sages connected the word "eichah" (alas! what has befallen us?) that begins Lamentations and the word "ayekah" ("Where art thou"), the question addressed to Adam and Eve after they had eaten the forbidden fruit. Vegetarians are also asking "where art thou". What are we doing re widespread world hunger, the destruction of the environment, the brutal treatment of farm animals, etc.? Perhaps failure to properly hear and respond to "ayekah" in terms of stating "hineni" - here I am, ready to carry out God's commandments so that the world will be better - causes us to eventually have to say and hear "eichah".
6. The book of Lamentations was meant to wake up the Jewish people to the need to return to God's ways. Since vegetarianism is God's initial diet (Genesis 1:29), vegetarians are also hoping to respectfully alert Jews to the need to return to that diet.
7. Rabbi Yochanan stated "Jerusalem was destroyed because the residents limited their decisions to the letter of the law of the Torah, and did not perform actions that would have gone beyond the letter of the law" ('lifnim meshurat hadin') (Baba Metzia 30b). In the same way, perhaps, many people state that they eat meat because Jewish law does not forbid it. Vegetarians believe that in this time of factory farming, environmental threats, widespread hunger, and epidemics of chronic degenerative diseases, Jews should go beyond the strict letter of the law and move toward vegetarianism.
8. Tisha B'Av has been a time of tears and tragedy throughout Jewish history. Animal-based diets are also related to much sorrow today due to its links to hunger and environmental destruction.
9. Tisha B'Av is not only a day commemorating destruction. It is also the day when, according to Jewish tradition, the Messiah will be born, and the days of mourning will be turned into joyous festivals. According to Rabbi Abraham Isaac Hakohen Kook, the Messianic period will be vegetarian. He based this view on the prophecy of Isaiah, "The wolf will dwell with the lamb . . .the lion will eat straw like the ox . . . and no one shall hurt nor destroy in all of God's holy mountain" (Isaiah 11: 6-9).
10. The readings on Tisha B'Av help to sensitize us so that we will hear the cries of lament and change our ways. Vegetarians are also urging people to change their diets, to reduce the cries of lament of hungry people and of animals.
11. The first Temple was destroyed because the people committed three cardinal sins: idolatry, immorality, and bloodshed (Yoma 9b). Animal-based diets today have links to these sins; (1) we have made our stomachs an idol and will do almost anything to appease it; (2) a diet that wastes so much grain and other agricultural resources while millions of people lack adequate food can be considered immoral; (3) there is much bloodshed from the 9 billion farm animals that are slaughtered annually in the United States alone to satisfy people's appetites for meat.
12. After the destruction of the second Temple, the Talmudic sages indicated that Jews need not eat meat in order to rejoice during festivals. They stated that the drinking of wine would suffice, (Pesachim 109a)
13. More than a day of lamentation, Tisha B'Av is also a day of learning - learning essential lessons about our terrible past errors so that they will not be repeated. Vegetarians believe that if people learned the incredible realities related to the production and consumption of meat, many would change their diets so as to avoid continuing current errors.
14. After the destruction of Jerusalem, while sighing and searching frantically for food, the people proclaimed, "Look God and behold what happened to me because I used to be gluttonous!" (Lamentations 1:11). Today too, gluttony (excessive consumption of animal and other products) is leading to widespread hunger and destruction.
15. The Book of Lamentations ends with "Chadesh yamenu k'kedem - make new our days as of old." We can help this personal renewal occur by returning to the original human diet, the vegetarian diet of Gan Eden (the Garden of Eden), a diet that can help us feel renewed because of the many health benefits of plant-based diets.
16. On Tisha B'Av, Jews do not wear leather shoes; one reason is that while commemorating events that involved so much death, we do not want to wear something manufactured from animal skin, a product derived from the deaths of another Divinely-created living being.
17. The Book of Lamentations has many very graphic descriptions of hunger. One is: "The tongue of the suckling child cleaves to its palate for thirst. Young children beg for bread, but no one extends it to them." Today, major shortages of food in the near future are being predicted by the Worldwatch Institute, a Washington DC think tank, and others, and one major reason is that people in China, Japan, India, and other countries where affluence has been increasing are moving to animal- entered diets that require vast amounts of grain.

In view of these and other connections, I hope that Jews will enhance their commemoration of the solemn but spiritually meaningful holiday of Tisha B'Av by making it a time to begin striving even harder to live up to Judaism's highest moral values and teachings, and one important way to do this is by moving toward a vegetarian diet.