The infinite library of the Universe is in your mind.

The cheerful mind perseveres and the strong mind hews its way through a thousand difficulties.

It is the calm, forgiving, equable, well-balanced mind that does the greatest amount of work.

Happiness depends more upon the internal frame of a person's own mind than on the externals in the world.

There is nothing so disobedient as an undisciplined mind, and there is nothing so obedient as a disciplined mind.

More than those who hate you, more than all your enemies, an undisciplined mind does greater harm.