Light: electromagnetic radiation from our sun that’s constantly bouncing off the world around us and illuminating it. To perceive this we need special organs to translate the waves into images within our brains: eyes. Without the ability to see, we’d have very little awareness of light, and even less interest.
When God says He is light (1Jn 1:5), perhaps He’s telling us that He’s not only truth, but also the means by which we perceive it.
God defines reality, both in the physical and metaphysical. He is not only truth itself (Jn 14:6), but also the ultimate standard by which everything has measure and is measured.
As each aspect of the spiritual dimension reflects the streaming revelation of God, its nature is revealed. In reacting to His Word, God exposes, illuminates, and reveals the spiritual detail of every sentient being (Is 8:20), and the color and texture of every moral choice we face, if only we have eyes to see. (Ps 119:105)
As C.S. Lewis said so well, let us believe in God as we believe the sun has risen, not only because we see it, but also because by it we see everything else.
Asking God to open our eyes is wanting to see the Light, to see Him in all things, and how all things relate to Him. It’s wanting to be aligned with, connected and engaged with Him. Once we can see, walking in the light with God is natural. (1Jn 1:7)