From Gandhi the Man: How One Man Changed Himself to Change the World by Eknath Easwaran:
"Perfect love," the Bible says, "casts our fear." Ahimsa [in the Hindu and Buddhist tradition, the principle of nonviolence toward all living things] is perfect love. It is the farthest thing from mere sentimentality; it is a lifelong challenge, a lifelong battle within oneself, full of challenges and trial so severe that those who tread the path of love in every religious tradition have called it sharper than a razor's edge. Gandhi used to put the matter bluntly: When another person's welfare means more to you than your own, when even his life means more to you than your own, only then can you say you love. Anything else is just business, give-and-take. To extend this love even to those who hate you is the farthest limit of ahimsa. It pushes at the boundaries of consciousness itself.