"What does not transmit light creates darkness."

"First learn the meaning of what you say, and then speak."

"When you have decided that a thing is good, and you cling to it, and you are not disturbed by it, then you have found your true good."

"What, then, is the fruit of these doctrines? Tranquillity, fearlessness, freedom."

"Freedom and slavery, the one is the name of virtue, and the other of vice, and both are acts of the will."