"God is light." This is a metaphor - a figure of speech. And in that view, it might suggest a world of varied analogies between the nature of God and the nature of the material element of light. Light is diffusive, penetrating, searching; spreading itself over all space, and entering into every hole and corner. It is quickening and enlivening; a minister of healthy vigour and growth to all living creatures, plants and animals alike, including man himself. It is pleasant also ; a source of relief and gladness to those who bask in its bright and joyous rays.
But there are two of its properties that may be singled out as specially relevant to this great comparison.In the first place, light is clear, transparent, translucent ; patent and open, always and everywhere, as far as its free influence extends. The entrance of light, which itself is real, spreads reality all around. Clouds and shadows are unreal; they breed and foster unrealities. Light is the naked truth. Its very invisibility is, in this view, its power. It is not seen because it is so pure.
For, secondly, a certain character of inviolability belongs to it, in respect of which, while it comes in contact with all things, it is itself affected by nothing. It kisses carrion ; it embraces foul pollution ; it enters into the innermost recesses of the rottenness in which worms uncleanly revel. It is the same clear element of light still; taking no soil; contracting no stain; - its brightness not dimmed, nor its viewless beauty marred. It endureth for ever, clean and clear.
Now, when it is said, "God is light;" when he says it of himself; when he makes it his own personal and special message to us, which his apostles and ministers are to be always receiving of him and declaring to us - the one heavenly telegram, or express telegraphic despatch, which they are to be reading to us and we are to be reading to our neighbours, that we may have fellowship, all of us together, with the Father and with his Son Jesus Christ - let not our imaginations wander in a wilderness of fanciful resemblances. Let these two thoughts be fixed in our minds; first, the thought of perfect openness ; and secondly, the thought of perfect inviolability. Let these be our thoughts of God, and of his essential character, as being, and declaring himself to be, " light." Thus " God is light."
-Robert S. Candlish