For an act to be moral the intention must be based on compassion, not duty. We do something because we want to do it, because we feel we have to do it, not because we ought to do it. And even if our efforts fail - or we never even get to implement them - we are still moral because our motivation was based on compassion.
The indifference, callousness and contempt that so many people exhibit toward animals is evil first because it results in great suffering in animals, and second because it results in an incalculably great impoverishment of the human spirit.
Unfortunately, love and compassion have been omitted from too many spheres of social interaction for too long. Usually confined to family and home, their practice in public life is considered impractical, even naive. This is tragic.
When we speak of a calm state of mind or peace of mind, we shouldn't confuse that with an insensitive state of apathy. Having a calm or peaceful state of mind doesn't mean being spaced out or completely empty. Peace of mind or a calm state of mind is rooted in affection and compassion and is sensitive and responsive to others.
The compassion we feel normally is biased and mixed with attachment. Genuine compassion flows towards all living beings, particularly your enemies. If I try to develop compassion towards my enemy, it may not benefit him directly, he may not even be aware of it. But it will immediately benefit me by calming my mind. On the other hand, if I dwell on how awful everything is, I immediately lose my peace of mind.
For fear of causing terror to living beings, Mahamati, let the Bodhisattva who is disciplining himself to attain compassion, refrain from eating flesh.
Let us have compassion for those under chastisement. Alas, who are we ourselves? Who am I and who are you? Whence do we come and is it quite certain that we did nothing before we were born? This earth is not without some resemblance to a gaol. Who knows but that man is a victim of divine justice? Look closely at life. It is so constituted that one senses punishment everywhere.