A good conscience fears no witness, but a guilty conscience is solicitous even in solitude. If we do nothing but what is honest, let all the world know it. But if otherwise, what does it signify to have nobody else know it, so long as I know it myself? Miserable is he who slights that witness.

A friend always loves, but he who loves is not always a friend.

While we teach, we learn.

It is the superfluous things for which men sweat.

Vice is contagious, and there is no trusting the sound and the sick together.

The mind unlearns with difficulty what it has long learned.

... frugality makes a poor man rich.