To devote your life to the good of all and to the happiness of all is religion. Whatever you do for your own sake is not religion.

I have never seen the slightest scientific proof of the religious ideas of heaven and hell, of future life for individuals, or of a personal God.

To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo.

Religion is the opiate of the masses.

The imaginary flowers of religion adorn man's chains. Man must throw off the flowers, and also the chains.

Religion is only the illusory sun which revolves round man as long as he does not revolve round himself.