Ahimsa (Nonviolence) is listed as the highest principle among all others in the ancient Patanjali’s Yoga Sutras of Maharishi Patanajali.
Indeed, it is the universal declaration of sages in all spiritual traditions that one should not harm other living beings as the same life energy permeates everyone.
All beings love life, want to be happy, and thrive. According to the law of karma, what one gives to others, one gets as well. Therefore, the secret to happiness is simply to support others in finding their joy.