Meat-eating and War
During thousands and hundreds of years,
the hatreds and viciousness in meats
in people's dining utensils,
are as deep as sea,
and are hardly to cease.
If one wants to know why there are wars in the world,
just listen to the thrilling screams
from a slaughter house
This is a well-known Buddhist poem, which reveals the connection between Meat-eating and War.
Meat-eating causes hatred, and hatred may cause war.
The hatreds arouse when an animal is killed, and when someone eats that animal's meat, the hatreds, and the thoughts of vengeance, will enter the eater's body together with the meat.
Those hatreds and thoughts of vengeance can accumulate in one's body, making him become more and more depressed, dislike others, easy to be angry, easy to conflict with others, etc. and when a large number of people (e.g. people in a nation) are dominated by these emotions, that may cause war.
Those hatreds and thoughts of vengeance will pollute and block one's heart, make his heart closed, as hard as stone, and become a great obstruction against enlightenment. A philosopher with evil inclination, who preaches the doctrines that supports violence, massacre, and anti-religion behaviors, may emerge under such a circumstance.
If one can renounce meat-eating, those pollutions will not continue to accumulate in his body and on his heart, but those pollutions will not be cleansed automatically. One also need to renounce killing, and practice some Dharmas (e.g. some Dharanis, mantras, repentances, etc ) which can cleanse those negative karmas.
For example, the Vajra-sattva Heart Mantra, Ksitigarbha Bodhisattva Sutra, Great Compassion Dharani, Great Compassion Repentance, Shurangama Mantra, Six Words Great Enlightening Dharani, etc. are very powerful and efficient for bad karma cleansing. Their Dharma-streams can wash your heart, soften your heart, make your heart open for enlightenment, and make you an inartificial virtuous person.