Just as the grammarian makes one study grammar,
A Buddha teaches according to the tolerance of his students;
Some he urges to refrain from sins, others to do good,
Some to rely on dualism, other on non-dualism;
And to some he teaches the profound,
The terrifying, the practice of enlightenment,
Whose essence is emptiness that is 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.
Compassion is something we can count on. Even if we face economic problems and our fortunes decline, we can still share our compassion with our fellow human beings. National and global economies are subject to many ups and downs, but through them all we can retain a compassionate attitude that will carry us through.
Anger cannot be overcome by anger. If someone is angry with you, and you show anger in return, the result is a disaster. On the other hand, if you control your anger and show its opposite - love, compassion, tolerance and patience - not only will you remain peaceful, but the other person's anger will also diminish.
True happiness comes from having a sense of inner peace and contentment, which in turn must be achieved by cultivating altruism, love and compassion, and by eliminating anger, selfishness and greed.
Without religion, also there is a way, it could be this way, through education, through scientific findings, then you get conviction. Not necessarily really love other, but for their own interest they are showing love, compassion to other like that.