These are quotes I’ve found inspiring, useful, truthful, and tools to meditate on. I hope that they will inspire you to think, challenge, question and learn as well as for you to share with others.
“I believe the first test of a truly great man is his humility. I do not mean by humility, doubt of his own powers. But really great men have a curious feeling that the greatness is not in them, but through them. And they see something divine in every other man.”
–John Ruskin
”I am only one, but still I am one. I cannot do everything, but still I can do something; and because I cannot do everything, I will not refuse to do something that I can do.” ~Helen Keller
”Maturity is the capacity to withstand ego destroying experiences, and not lose one’s perspective in the ego-building experiences.” – Robert K Greenleaf
“Happiness cannot be traveled to, owned, earned, worn or consumed. Happiness is the spiritual experience of living every minute with love, grace, and gratitude.”~Denis Waitley
“I never met a bitter person who was thankful. Or a thankful person who was bitter.” Nick Vujicic
”There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”
Albert Einstein
“When one door closes another door opens; but we so often look so Long and so regretfully upon the closed door, that we do not see the ones which open for us.” –Alexander Graham Bell

Albert Einstein has a playful mind. Was he spiritual i wonder? He was such a quintessential scientist.
I would think that he had some of the Stoics Spirituality going for him… ;D Here’s a list of some of his quotes…I have no doubt that he was a very spiritual being ;D http://rescomp.stanford.edu/~cheshire/EinsteinQuotes.html