Man often becomes what he believes himself to be. If I keep on saying to myself that I cannot do a certain thing, it is possible that I may end by really becoming incapable of doing it. On the contrary, if I have the belief that I can do it, I shall surely acquire the capacity to do it even if I may not have it at the beginning.
Enjoy the blessing of strength while you have it and do not bewail it when it is gone, unless, forsooth, you believe that youth must lament the loss of infancy, or early manhood the passing of youth. Life's race-course is fixed; Nature has only a single path and that path is run but once, and to each stage of existence has been allotted its own appropriate quality; so that the weakness of childhood, the impetuosity of youth, the seriousness of middle life, the maturity of old age.. each bears some of Nature's fruit, which must be garnered in its own season.
So sometimes things are ahead and sometimes they are behind; Sometimes breathing is hard, sometimes it comes easily; Sometimes there is strength and sometimes weakness; Sometimes one is up and sometimes down. Therefore the sage avoids extremes, excesses, and complacency.
My opportunities were still there, nay, they multiplied tenfold; but the strength and youth to cope with them began to fail, and to need eking out with the shifty cunning of experience.
Shallow men believe in luck, believe in circumstances: it was somebody's name, or he happened to be there at right time, or it was so then, and another day it would have been otherwise. Strong men believe in cause and effect.
My first meditation teacher told me that there is no such thing as a bad meditation. He was right. During the difficult meditations you build up your strength, which creates meditation for peace.