A man's ethical behaviour should be based effectually on sympathy, education, and social ties and needs; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death.
Those who show pity and are always ready to help during times of trouble are seldom the same ones who rejoice in our joy: when others are happy they have nothing to do, they become superfluous and lose their feeling of superiority, and so they easily show their displeasure.
At the same time, as social beings, we are moved in the relations with our fellow beings by such feelings as sympathy, pride, hate, need for power, pity, and so on.