The control of the activity of mind is called concentration in the language of the mystics. The meaning of this word is often not rightly understood. People are apt to think that concentration means only closing the eyes. But one may close one's eyes for hours, and still the thoughts keep coming like a moving picture. People are never at rest, never at peace; anxiety and sorrow do not disappear just because they close their eyes. It is concentration that does that. Concentration is activity of mind in the direction desired; our desire dictates in which way the mind is to be active; the mind acts according to our wishes.
Hazrat Inayat Khan