Reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.

So long as one believes in God, one has the right to do the Good in order to be moral.

The Church says that the earth is flat, but I know that it is round, for I have seen the shadow on the moon, and I have more faith in the shadow than in the Church.

I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.

Religion is by no means a proper subject of conversation in mixed company.

The nature of God is a circle, of which the center is everywhere and the circumference is nowhere.

The state dictates and coerces; religion teaches and persuades. The state enacts laws; religion gives commandments. The state is armed with physical force and makes use of it if need be; the force of religion is love and benevolence.

If God did not exist, it would be necessary to invent him.

Kill a man, and you are an assassin. Kill millions of men, and you are a conqueror. Kill everyone, and you are a god.

We have just enough religion to make us hate, but not enough to make us love one another.

God is a concept by which we measure our pain.

Among all nations, through the darkest polytheism glimmer some faint sparks of monotheism.

Talk to me about the truth of religion and I’ll listen gladly. Talk to me about the duty of religion and I’ll listen submissively. But don’t come talking to me about the consolations of religion or I shall suspect that you don’t understand.