As the inner and the outer are mirror reflections of each other, it is the inward gathering of thoughts that promotes the outward manifesting of those thoughts into physicality. And it is the outward expanding of thoughts that promotes the inward etherealizing of any physical creation that has been maintained by those thoughts. Concentration is the inward focusing of thoughts to materialize an idea. Inspiration is the expansive spacing out of thoughts - to dematerialize a materialized idea or to gather new ideas.
Concentration promotes the outward materializing force.
Inspiration promotes the inward etherealizing force. Concentration does to thoughts what a magnifying lens does to light - it focuses the thoughts into a narrower beam of higher intensity. Just as a lense can concentrate sun light to the point of being able to light a leaf on fire, likewise concentration can gather together the thoughts, making them more inter-related, and more aligned with common Intent , or unified purpose , or oneness of image . Focusing consciousness through concentration produces the automatic tendency of universal light substance to materialize the image held by those concentrating thoughts. As any of these factors increase, manifestation occurs more quickly.