The book one must read to learn natural sciences is the book of nature. The book from which to learn religion is your own mind and heart.

Take up one idea. Make that one idea your life - think of it, dream of it, live on that idea. Let the brain, muscles, nerves, every part of your body, be full of that idea, and just leave every other idea alone. This is the way to success.

...Really, there is no greater sin than cowardice; cowards are never saved - that is sure. I can stand everything else but not that.

Knowledge can only be got in one way, the way of experience; there is no other way to know.

The test of ahimsa is the absence of jealousy. The man whose heart never cherishes even the thought of injury to anyone, who rejoices at the prosperity of even his greatest enemy, that man is the bhakta, he is the yogi, he is the guru of all.

Give up all desire for enjoyment in earth or heaven. Control the organs of the senses and control the mind. Bear every misery without even knowing that you are miserable. Think of nothing but spiritual freedom.

There cannot be a cause without an effect, the present must have had its cause in the past and will have its effect in the future.