The Buddha on Animal Liberation

“A disciple of the Buddha should have a mind of compassion and cultivate the practice of liberating sentient beings . He must reflect thus: throughout the eons of time, all male sentient beings have been my father , all female sentient beings my mother. I was born of them, if I slaughter them, I would be slaughtering my parents as well as eating flesh that was once my own. This is so because all elemental earth, water, fire and air—the four constituents of all life—have previously been part of my body, part of my substance. I must therefore always cultivate the practice of liberating sentient beings and enjoin others to do likewise —as sentient beings are forever reborn, again and again, lifetime after lifetime. If a Bodhisattva sees an animal on the verge of being killed, he must devise a way to rescue and protect it, helping it to escape suffering and death. The disciple should always teach the Bodhisattva precepts to rescue and deliver sentient beings.”

(From the Brahma Net Sutra.)