In his book, Raja Yoga, Yogi Ramacharaka (William Walker Atkinson) says about the power of attention:
“The word Attention is derived from two Latin words “ad tendere,” meaning “to stretch toward,” which is really what attention is.
The “I” wills that the mind be focused on some particular object or thing, and the mind obeys and “stretches toward” that object or thing, focusing its entire energy upon it, observing every detail, dissecting, analyzing, consciously and sub-consciously, drawing to itself every possible bit of information regarding it, both from within and from without.
We cannot lay too much stress upon the acquirement of this great faculty, or rather, the development of it, for it is necessary for the intelligent study of Raja Yoga.”
“Attention has been defined as a focusing of consciousness, or, if one prefers the form of expression, as “detention in consciousness.”
“In the first case, we may liken it to the action of the sun-glass through which the sun’s rays are concentrated upon an object, the result being that the heat is gathered together at a small given point, the intensity of the same being raised many degrees until the heat is sufficient to burn a piece of wood, or evaporate water. If the rays were not focused, the same rays and heat would have been scattered over a large surface, and the effect and power lessened.”