Concentration is one-pointedness of mind. The ability to hold the awareness of the mind on one point, one place, without wavering. The perfection of concentration leads to meditation. In the state of concentration, the mind is not aware of the external environment or of other peripheral things that surround the object of concentration.
Why is concentration so important? This can be best answered by comparing the mind to a light bulb. The rays of light from the bulb go out in all directions; the energy spreads. If you stand five feet away from the bulb, you can see the light but cannot feel the heat, even though there is great heat at the centre of the bulb, at the filament. In the same way, the mind has great power in potential form, but it is dissipated in all directions. The mind thinks of different things one after another, without dwelling in depth on any particular subject. Therefore, the average mind does not utilize its power.
In recent times, science has produced the laser and many advances have been made in modern technology through its use. It is a method whereby all the rays of light from a source are lined up with each other so that they go in the same direction and in unison with each other. They vibrate in harmony with each other. The original source of light need not be any greater than the light bulb we have just discussed, yet if you were to stand five feet from a laser beam source, the beam would burn a hole straight through your body. This is the difference between ordinary light and concentrated light.
Similarly, concentrated thought also has great power. It has the power of heightened perception, the ability to see more of the underlying truth behind phenomena. It has the ability to achieve great things and to do unimaginable amounts of work. A concentrated mind is also a relaxed mind. Whenever you become deeply engrossed in anything you automatically come to a state of relaxation. Concentration is vital for everything that you do in life because it prevents the mind from wandering aimlessly in all directions. You only need a look around you to see the truth of this statement.
Work done with a concentrated mind becomes more enjoyable. A person with concentrated mind can do all kinds of work with great efficiency. A person who is unable to concentrate, who thinks of other things while doing the work at hand, makes mistakes and takes an unnecessary length of time to complete the task, if he ever completes it at all. He will continually think about how slowly the time is passing. He will worry about himself, his problem, his family, while he is working. Due to poor concentration there is poor application, so the work is not properly done. Therefore, concentration is essential in daily life as well as in spiritual practice.
Extracted from Dharna Darshan by Swami Niranjanananda Saraswati