Whatever you may want to do in life, one thing is absolutely indispensable and at the basis of everything, the capacity of concentrating the attention. If you are able to gather together the rays of attention and consciousness on one point and Can maintain this concentration with a persistent will, nothing can resist it - whatever it maybe, from the most material physical development to the highest spiritual one. But this discipline must be followed in a constant and, it may be said, imperturbable way; not that you should always be concentrated on the same thing- that's not what I mean, I mean learning to concentrate.
  And materially, for studies, sports, all physical or mental development, it is absolutely indispensable. And the value of an individual is proportionate to the value of his attention.
  And from the spiritual point of view it is still more important. There is no spiritual obstacle which can resist a penetrating power of concentration. For instance, the discovery of the psychic being, union with the inner Divine, opening to the higher spheres, all can be obtained by an intense and obstinate power of concentration - but one must learn how to do it.
  There is nothing in the human or even in the superhuman field, to which the power of concentration is not the key.
  You can be the best athlete, you can be the best student, you can be an artistic, literary or scientific genius, you can be the greatest saint with that faculty. And everyone has in himself a tiny little beginning of it -it is given to everybody, but people do not cultivate it.