One who is injured ought not to return the injury, for on no account can it be right to do an injustice.

I was afraid that by observing objects with my eyes and trying to comprehend them with each of my other senses I might blind my soul altogether.

I do nothing but go about persuading you all, old and young alike, not to take thought for your persons or your properties, but and chiefly to care about the greatest improvement of the soul.

Knowing thyself is the height of wisdom.

Why do you wonder that globetrotting does not help you, seeing that you always take yourself with you? The reason that set you wandering is ever at your heels.

An envious man waxeth lean with the fatness of his neighbors. Envy is the daughter of pride, the author of murder and revenge, the beginner of secret sedition and the perpetual tormentor of virtue. Envy is the filthy slime of the soul; a venom, a poison, or quicksilver which consumeth the flesh and drieth up the marrow of the bones.

To be uncertain is to be uncomfortable, but to be certain is to be ridiculous.