From the scientific view, the theory of karma may be a metaphysical assumption -- but it is no more so than the assumption that all of life is material and originated out of pure chance
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.
Go forth in every direction- for the happiness, the harmony, the welfare of the many. Offer your heart, the seeds of understanding, like a lamp overturned and re-lit, illuminating the darkness.
Never think there is anything impossible for the soul. It is the greatest heresy to think so. If there is sin, this is the only sin; to say that you are weak, or others are weak.