Knowledge ... shall always bear witness like a clarion to its creator.

The grave will fall in upon him who digs it.

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

When Fortune comes, seize her in front with a sure hand, because behind she is bald.

Fix your course on a star and you'll navigate any storm.

Every part is disposed to unite with the whole, that it may thereby escape from its own incompleteness.

It vexes me greatly that having to earn my living has forced me to interrupt the work and to attend to small matters.