In Khedrup Je's commentary on The Three Vows, it is said that, on the whole, only the Bodhisattvas are required to abstain from meat. Therefore, all who have taken the vow of bodhichitta, whether they be monks, nuns, or lay people, must abstain from meat. For if Bodhisattvas, who have thus become an object of praise, eat meat, a strong desire for the taste of it will grow in them. As a result, their compassion will wane. Therefore the fully ordained, the shramaneras, kings, ministers, leaders, and lay people who practice the Mahayana should refrain from eating meat.

Khedrup Je predicted that even those who have taken the Bodhisattva vow, even those who have recited the formula of bodhichitta hundreds of times will not consider even the conscious killing of thousands of animals or the inducing of others to do the same as wrong; no need to talk about their abstinence from meat. He was so right, and we can see that in our own days his prophecy has come to pass!

Therefore we must regard the eating of meat as contrary to the teachings. We must get used to the idea that it is wrong to crave meat, and we must reject it! If we think to ourselves, "How good meat is for us. How clean and wholesome it is. How delicious it tastes!" the consequence will be that whenever meat and blood are placed before us - as if it were no more than rice and tsampa, milk and butter--we will feel an intense craving and we will be unable to resist. This is why Khedrup Je said that just as we are about to put it in our mouths, we should reflect that the meat is something filthy, that has arisen from sperm and blood. Furthermore, we should remember that the flesh has come from beings who have been, from beginning less time, our own mothers and our own children. And we should conclude that it is deeply wrong to crave their meat, just as it would be utterly terrible to long for the flesh of our own children!

We should ponder the dangers implicit in the desire for meat and reflect, in accordance with the teachings, that if we go hunting and fishing, we are turning into butchers and killers, If we buy meat, we are inciting others to kill animals for their flesh. If we sell the meat of slaughtered beasts for profit, if we long for meat, we are like Senge Bangzang and Prince Kangtra, who killed human beings and devoured their flesh. Smelling the revolting odor, animals will flee from us. It is said that the accomplishment of the vidya mantra and the development of great love and compassion will be impeded.

Therefore, in our desire for meat, we should never say that the Vinaya advocates the eating of meat. It is said that never, even in our dreams, should we say that meat eating is without fault. Experience proves that when people who aspire to enlightenment and cultivate bodhichitta eat meat, their compassion weakens and their determination with it. On the other hand, it is taught that when people keep themselves in check in order to curb their desire for the taste of meat, and when they abstain from meat of every kind, pure or impure in the three ways - both the meat of slaughtered animals and of animals that have died naturally - this truly a great wonder!

(Source: FB, p. 87-88)