I want, by understanding myself, to understand others. I want to be all that I am capable of becoming. - Mansfield, Katherine

He knows the universe and does not know himself.

Before a man can wake up and find himself famous he has to wake up and find himself.

Know yourself, master yourself, conquest of self is most gratifying. - Unknown, Source

He that knows himself, knows others; and he that is ignorant of himself, could not write a very profound lecture on other men's heads.

Other men's sins are before our eyes; our own are behind our backs.

Know thyself? If I knew myself I would run away.

If people can be educated to see the lowly side of their own natures, it may be hoped that they will also learn to understand and to love their fellow men better. A little less hypocrisy and a little more tolerance towards oneself can only have good results in respect for our neighbor; for we are all too prone to transfer to our fellows the injustice and violence we inflict upon our own natures.

Explore thyself. Herein are demanded the eye and the nerve.

There are three things extremely hard: steel, a diamond, and to know one's self.