Q: What is concentration?
It is to bring back all the scattered threads of consciousness to a single point, a single idea. Those who can attain perfect attention succeed in everything they undertake; they will al ways make a rapid progress. And this kind of concentration can be developed exactly like the muscles; one may follow different systems, different methods of training. Today we know that the most pitiful weakling, for example, can with discipline become as strong as anyone else. One should not have a will which flickers out like a candle. The will, the concentration must be cultivated; it is a question of method, of regular exercise. If you will, you can. But the thought “What’s the use?” must not come in to weaken the will. The idea that one is born with a certain character and can do nothing about it is a stupidity.
Ref: The Sunlit Path