Montesquieu

When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty; because apprehensions may arise, lest the same monarch or senate should enact tyrannical laws, and execute them in a tyrannical manner.

Again, there is no liberty, if the power of judging be not separated from the legislative and executive powers. Were it joined with the legislative, the life and liberty of the subject would be exposed to arbitrary control; for the judge would be then the legislator. Were it joined to the executive power, the judge might behave with all the violence of an oppressor.

It is not the young people that degenerate; they are only rather thoughtless: the old ones are corrupt.

Slavery is not only natural but useful to certain peoples.

As all men are born equal, slavery is against nature.

I have never heard of anything so insolent as to propose to the English Parliament to give up their liberty by their own consent.

The greatest empires are not maintained by the same means by which they are established. A new force may be acquired by conquest, but this new force will diminish the old.

In a true democracy, the people are sovereign, and the magistrates are only its ministers.

The political liberty of the subject is a tranquility of mind, arising from the opinion each person has of his safety.

The custom of exposing children was very frequent among the Greeks, because they had no families.

The principle of democracy is corrupted not only when the spirit of equality is extinct, but likewise when they fall into a spirit of extreme equality, and when every citizen wants to be equal to those whom he chooses to command him.

Luxury is the excess of riches.

There is no nation in the world that has more need of religion than the English.

The tyranny of a prince is not so dangerous to the public welfare as the apathy of a citizen in a democracy.

The savage peoples of America, who are fond of their liberty, and are passionately attached to their country, will not change their way of life for any other.

It is impossible for us to suppose that these are men; because if we should suppose them to be men, one would begin to believe that we ourselves are not Christians.

In moderate governments, the love of the country, shame, and the fear of blame are restraining motives, which may prevent many crimes.

Countries are not cultivated in proportion to their fertility, but to their liberty.

The Romans, having subjected the world, were themselves subjected to their own laws, and to the caprices of their magistrates.

Trade is the profession of a people who have renounced all other professions.