"He, however, who is united to God by faith and recognizes Him by action is indeed enabled to see Him by contemplation.  He see things of which I am not able to write.  His mind sees strange visions and is wholly illuminated and becomes like light, yet he is unable to conceive of them or describe them.  His mind is itself light and sees all things as light, and the light has life and imparts light to him who sees it."  ~St. Symeon the New Theologian

The Light that St. Symeon is talking about is spiritual light,  that light that comes from God and to us through the spiritual sun.  It is the Light that awakened St. Francis that morning as he looked out of his window at dawn and which gave him the ability to see that all things have a spirit and that spirit is essentially the same for all beings.  It is that Light which feeds the soul, the only thing that can nourish the soul and allow it to grow and thrive in a world of materialism.  It is that Light which will provide the energy to make our world once more a world of God, a world of spirit.  But that will happen only if we we help to make it happen.

Note: from the second sentence in this quote from "The Discourses" by St. Symeon (He see things of which I am not able to write.),
It is clear that Symeon recognized the need to keep advanced spiritual information from the uninitiated and to teach it only in a proper spiritual setting and in a spiritual school by a spiritual teacher able to recognize when the student is ready for the information.