He who is by nature not his own but another's man is by nature a slave.

It is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician demonstrative proofs.

The character which results from wealth is that of a prosperous fool.

It has been well said that 'he who has never learned to obey cannot be a good commander.' The two are not the same, but the good citizen ought to be capable of both; he should know how to govern like a freeman, and how to obey like a freeman - these are the virtues of a citizen.

Jealousy is both reasonable and belongs to reasonable men, while envy is base and belongs to the base, for the one makes himself get good things by jealousy, while the other does not allow his neighbour to have them through envy.

A body in motion can maintain this motion only if it remains in contact with a mover.

Even when laws have been written down, they ought not always to remain unaltered.