While on the subject of quotations, another of my favorites is from The Meditations of Marcus Aurelius, a Roman emperor and stoic philosopher, who lived around 100 AD. Most people now know him as the aging emperor played by Richard Harris in the movie Gladiator or as quoted by Hannibal Lector in Silence of the Lambs. Besides the one quoted by Hannibal, one of my favorites is:
“The mind is like a sponge and becomes dyed with the color of its thoughts.”
Again, great psychological insight centuries before the science of psychology was invented.