"Thought expands into expression, as mortals shake off their swaddling clothes. 'Let there be light,' is the perpetual demand of Truth and Love, changing chaos into order, and discord into the music of the spheres" (Science and Health with Key to the Scriptures by Mary Baker G. Eddy, p. 151).
We make an environment for ourselves, that is, we reflect our mental pictures on our circumstances, just as we reflect them on the body. The perpetual demand for Light in the world about us, which we term our environment, changes chaos into order, until our circumstances expand into the expression of our thought. Expression is but the following of a thought. The thought of Light preceded the expression of it. God said, "Let there be Light, and there was Light." He spoke into visible manifestation a concept of Mind.
Man, as a reflection of God, necessarily must reflect this power of making Light manifest, not only where disease lurks, but where circumstances seem in chaos and darkness. Reflecting God's power, we shape a new world all about us.