Love is the sign of intelligence. Where there is no intelligence there is no love. Rocks have no intelligence and there is no love in them. Plants and trees have awakened to life and show some attachment. If we have a plant and care for it, it will respond to our care and flourish. Animals have more intelligence and show much affection and attachment. Pet animals in the house grow to have much affection and sympathy for their master; they are happy in his joy and become sad in his sorrow. Horses too show much affection. It is told that the horse of an Arab who had been wounded in battle stayed beside him for three days and nights, until his comrades came and rescued him. Man has the most intelligence, and he has the most love in his nature.