Nikos Kazantzakis said this quote

I tried to establish order over the chaos of my imagination, but this essence, the same that presented itself to me still hazily when I was a child, has always struck me as the very heart of truth. It is our duty to set ourselves an end beyond our individual concerns, beyond our convenient, agreeable habits, higher than our own selves, and disdaining laughter, hunger, even death, to toil night and day to attain that end. No, not to attain it. The self-respecting soul, as soon as he reaches his goal, places it still further away. Not to attain it, but never to halt in the ascent. Only thus does life acquire nobility and oneness.