"I am in earnest; I will not equivocate; I will not excuse; I will not retreat a single inch; and I will be heard."

"With reasonable men I will reason; with humane men I will plea; but to tyrants I will give no quarter, nor waste arguments where they will certainly be lost."

"Know thyself."

"There is no 'royal road' to geometry."

"I am an invisible man. No, I am not a spook like those who haunted Edgar Allan Poe; nor am I one of your Hollywood-movie ectoplasms. I am invisible, understand, simply because people refuse to see me."

"Those who want to live, let them fight, and those who do not want to fight in this world of eternal struggle do not deserve to live."

"We should every night call ourselves to an account: What infirmity have I mastered today? What passions opposed? What temptation resisted? What virtue acquired?"

"Whether you like it or not, history is on our side. We will bury you."