A desire arises in the mind. It is satisfied immediately another comes. In the interval which separates two desires a perfect calm reigns in the mind. It is at this moment freed from all thought, love or hate. Complete peace equally reigns between two mental waves.
SivanandaIf you focus the rays of the sun through a lens, they can burn cotton or a piece of paper; but, the scattered rays cannot do this act. If you collect the dissipated rays of the mind and focus them at a point, you will have wonderful concentration.
Sivananda