The mysteries of light have been pondered for millennia – what is this stuff actually, and how might it influence our lives? As one might expect, “light” finds its way onto the pages of scripture with over 200 references in the bible. We have a natural tendency to read and understand scripture through modern eyes, but did the ancient authors have the same understanding about light as we do today with modern physics? Decidedly not. When we try to understand scripture, to the best of our ability, we ought to interpret it based on the author’s understanding.
In the ancient near east, light, particularly from the sun, moon and stars, was understood to be a result of the activity of the gods. In Egypt, for instance, it was daylight when the eyes of Ra were open, and night time when his eyes were closed. Virtually every pantheon includes a god or goddess associated with sun and moon.
For what little they knew about light, they did understand we see things better when there is more light present. For Aristotle, light was a property relating to the transparency of the elements of water and air. Plato and Pythagoras believed sight resulted from rays which went out from the eyes, touched objects in the world and returned to the eyes. The causal connection between light and vision came much later during the medieval period (not the dark ages). At that time, it became understood light was produced from light sources, reflected off objects, entered our eyes, and was the cause for our ability to see.
The understanding of light in the Judeo-Christian tradition is distinct from its surrounding cultures. In the creation narrative, the author was very careful to indicate that light (whatever it is) is a created thing – its existence is neither a part of God nor tied to the activity of God. Further, the sources of light (sun, moon and stars) are also created things. The author describes them as “greater” and “lesser” lights – they are not given names – they are not things to be revered or worshipped.
This baseline understanding of light is important because, for most instances in scripture, light is used figuratively – we need not think these authors were referring to light that was coming from the sun or moon. Rather, a light from God is something that results in spiritual understanding. The psalmist writes, “For with you is the fountain of life; in your light do we see light.” (Psalm 36:9) It is through God that the best life is to be found, and that the understanding from God surpasses human understanding. Similarly, referring to Christ, the gospel writer says, “In him was life, and the life was the light of men. The light shines in the darkness, and the darkness has not overcome it.” (John 1:4-5)
All that said, I find it interesting how some of our modern understanding of light might serve to enrich the meaning of God/Christ being the “light of the world”. I take great caution here not wanting to suggest that our modern scientific understanding changes or improves our understanding of anything in scripture, but does give us some interesting things to ponder. In the list below, I have identified six aspects of light which were not understood by the biblical authors, but provide interesting connections to other spiritual truths about Christ:
Light is energy. The light energy from the sun becomes the energy which powers nearly every ecosystem on the planet. Photoautotrophs (e.g., plants, plankton) do not merely absorb the energy, they transform it via photosynthesis into chemical energy which can then be transferred to other organisms. That energy can be used in turn by these organisms to grow, change and move. For the Christian, there is spiritual power found in Christ. This power results in a transformation of the mind through which lives are changed enabling people to follow after God and accomplish His purposes on earth.
Light moves in a straight line. The Persian astronomer, Al-Hazan (~1,000 AD), in his seven-volume treatise on optics, was one of the first to describe the fact that light moves in a straight line. In scripture, righteous living is often described as going on a straight path. None would be more righteous and “straight” than Jesus himself – he is the “one who in every respect has been tempted as we are, yet without sin” (Hebrews 4:15). I recognize that the path of light can be altered (e.g. reflection, refraction, diffraction) and, in a sense, become crooked. Similarly, humans can take the good things of God (e.g., food, speech, sex) and corrupt them, and use them for evil purposes. While the pathway of light can be “bent”, it is still straight in between the points where its path is altered. Likewise, human behavior can never be completely crooked. C.S. Lewis recognized that, “wickedness, when you examine it, turns out to be the pursuit of some good in the wrong way.” In the end, however, it is Christ who will come and put thing aright – He will make the crooked straight.
Light allows us to see. When light reflects off objects it enters our eyes and provides the sense data by which we can both know about and understand our external world. When the light of Christ enters the life of Christians, they gain an understanding of the world which is not comprehended by the rest of the world. It is an understanding which enables them to have faith in Christ and do His will.
Light carries information. On one level our visual sense data is a type of information, but on another level, light can actually contain information. In a technique called absorption spectroscopy, light emitted from heated elements reveals a signature pattern of spectral lines unique to each element. When looking at the absorption spectrum from stars and galaxies, this gives us information both about the composition and movement of these objects. Humans use other parts of the electromagnetic spectrum to send information (e.g. radio waves and microwaves). It is interesting, then, that Christ is referred to both as the light of the world, and the Word of God. For the writers of both old and new testaments, it is the word of God which has transformative power and is embodied in Christ himself.
Light has a dual nature. In our attempts to understand light, we have come to realize that depending on what you make light do in an experiment, it can either behave like a particle or a wave. It cannot be said that sometimes light is a particle, and sometimes it is a wave – it is always both, as contradictory as that might seem. Christ is also understood to have a dual nature – He is both fully human and fully God. I would not say these dualities are in any way comparable, but the particle/wave duality of light lends plausibility to the notion that Christ can have a dual nature as well.
Light is the ultimate reference frame. Through Einstein’s theory of general relativity, we have come to understand that some things which were once thought to be absolute (e.g., space and time) are actually relative – especially when things get really big or go really fast. This does not commend philosophical relativism which throws everything up in the air. In General relativity, the changes which occur are relative to the one constant in the universe: the speed of light. Christ declared himself to be the truth – it is by him that all things in life are to be truly understood – it is with the truth of Christ we can be truly free.
Hopefully, you see here that our scientific understanding has not given us any new spiritual understanding, but it does help in this case to make some interesting connections – ones that would not have been associated with light by the biblical authors, but ones which have been revealed in scripture in other ways. These contemporary insights about light simply provide us an opportunity to reflect on the character of Christ (pun intended). To some degree, it also helps confirm the correspondence between the book of scripture and the book of nature.
 See 1 Corinthians 1:23-25; Romans 12:2; Philippians 1:6, 4:13
 See Psalm 5:8, Proverbs 3:5-6, Psalm 125:5, Proverbs 4:23-25, Luke 3:5. The quote by C. S. Lewis is from Mere Christianity (Macimillian, New York, NY, 1960),49.
 See 1 Corinthians 2:14; Colossians 1:9, 2:2; 1 John 5:20
 See Psalm 33:6, Isaiah 55:10-11, John 1:1-3, 1 Corinthians 1:18
 See Colossians 1:15-20; Philippians 2:6-8
 See John 1:14, 8:31-32, 14:6-7