The life of spies is to know, not be known.

There is nothing more deceptive than an obvious fact.

To know all is not to forgive all. It is to despise everybody.

If the world were good for nothing else, it is a fine subject for speculation.

Nothing is hidden from the eyes of the observing world.

The first duty of a good inquisitor is to suspect especially those who seem sincere to him.

I will never again command an army in America if we must carry along paid spies. I will banish myself to some foreign country first.

There is a sickness among tyrants: they cannot trust their friends.

For sooner will men hold fire in their mouths than keep a secret.