“Guard well within yourself that treasure, kindness. Know how to give without hesitation, how to lose without regret, how to acquire without meanness.”

lecture I: "The Uncertainty of Science"
The Meaning of It All (1999)

"Self Esteem" (31 May 2007)
Context: If you're coming into this YouTube thing, do it because of what you can do for other people... Don't worry so much about yourself, and if you're doing ok, and if you love yourself — you do, trust me. Think of what you can do for other people... Not some kind of self review, not some kind of day or week or however long to make sure you feel good about yourself — but thinking about the other people all around you, all the time, who could always — always use a hand, one way or another, even if it's kindness. Think of that instead. And maybe you are starting to notice my quote on the page "Look without, and you will be fulfilled within — without a doubt." I really mean that — look without, without of yourself — not within.

Letter to a friend (November 1920), as quoted in Peter Kropotkin : From Prince to Rebel (1990) by George Woodcock and Ivan Avakumovic, p. 428

Source: A History of Western Philosophy

Book Two in 'Absolution and Eternal Refuge', MG. (Note: Alternate translation of above passage ('Gods, my gods...'))
The Master and Margarita (1967)

p. 219 http://www.gutenberg.org/files/2162/2162-h/2162-h.htm#emancipation
The Tragedy of Woman's Emancipation (1906)

Source: How to Love

Source: A Mother's Advice to Her Son, 1726, p. 160