A prince who loves and fears religion is a lion who stoops to the hand that strokes or to the voice that appeases him. He who fears and hates religion is like the savage beast that growls and bites the chain, which prevents his flying on the passenger. He who has no religion at all is that terrible animal who perceives his liberty only when he tears in pieces, and when he devours.

I shall be obliged to wander to the right and to the left, that I may investigate and discover the truth.

The prejudices of superstition are superior to all others, and have the strongest influence on the human mind.

But constant experience shows us that every man invested with power is apt to abuse it, and to carry his authority as far as it will go.

If I knew something that would serve my country but would harm mankind, I would never reveal it; for I am a citizen of humanity first and by necessity, and a citizen of France second, and only by accident

An injustice to one is a threat made to all

Peace is a natural effect of trade.