Jesus Christ is the Light of the world.
How can a man, even the Son of Man, be a light? We see Christ depicted in art with a halo behind His head, which implies light, and the saints are likewise depicted, and we are all to be a light to the world, so is this light somehow an artistic metaphor?
Jesus spoke in parables, but He also spoke what were not parables. When He said I am the door, for example, people say He didn’t mean a literal door, but actually, yes, He did, He meant a door as in a doorway. A doorway is a narrow passage between two expanses, whether between 2 rooms in a house, or between the sheepfold and the outside world. In any case, despite His not meaning He was a wooden door, with a doorknob and a keyhole, which in any event is a closing, not an opening, He did in fact mean that He was a door, not as a parable or as a metaphor.
So, with that reasoning, how was He a light? What does a light do? It illuminates. It shows what would otherwise be hidden, or in darkness. What is the source of light? It is that which has the energy to burn brightly. A candle, a light bulb, the sun, are all the sources of light.
What is the ultimate source of all light? The ultimate source of light for all creation is the Creator. It is God the Father. Jesus Christ, God the Son, was the perfect image of the Father. If He is the perfect image of the Father, then He was, during His earthly ministry, the visible manifestation of the Father. The people of Judea saw God the Father when they saw God the Son. The Father, the source of Light, was illuminated through the Son. When they saw the Son, they saw the Father.
And today we see the same Light, albeit through a glass darkly. We have an image of the Son that illuminates the Father. The image of the Son most commonly seen in Catholic churches is the crucified Christ.
Now, the Father was not crucified. There is no wooden cross in Heaven that the Father hangs on, nothing of the sort. And yet, the Son, at this most crucial and pivotal moment of His earthly ministry and of human history, showed the Father in a way almost incomprehensible, unless we really try to understand it. Because we can only see it with the comprehension of the mind.
When we see an image of Jesus Christ, the Son of God, hanging on a cross, we are seeing with our eyes a picture of human agony, but remember God does nothing without a purpose. The purpose of the agony of the Son on the cross was His sacrifice to the Father for the propitiation of our sins. It was, in Catholic theology, the offering up by the High Priest of Himself as the pure Victim. It was a gift of Himself for, and as, our salvation.
So how does this relate to the Father, Who does not perform in His person the same sacrifice? What quality of the Father are we seeing illuminated by this sacrifice of the Son?
We are seeing the total self-giving of the gift of Creation to us. When we see Christ offering Himself nailed to a cross of wood, the fruit of the Tree of Life on the cross which is the Law, the fruit of the Tree of Knowledge of Good and Evil, we are seeing a total wedding of Himself to that fruit of Creation. The Father, likewise, in giving us His Creation, has given us all that He has to give, in order to draw us to Himself and even to wed us to Himself through His Son. The Father, Whom we think of in Old Testament terms as hard and uncompromising, has actually performed the ultimate act of self-giving in the Creation, which He has given to us. Remember that the Son is eternal like the Father, and that the purpose of Creation was for God to become man. When we see God the Son giving Himself completely, He is illuminating God the Father Who also gives Himself completely to His Creation.
A corollary of this is that the world we have been given is the best it could be. When we are born into the world, we are presented with the possibility of being born again into the Kingdom of Heaven. If we experience suffering, we embrace it as a means of bringing us closer to God. What appears terrible from the narrow perspective of this life is a means of causing us to pray and embrace God and thereby come to eternal life. Saint Faustina received the revelation of the Divine Mercy through an intimate relationship with Jesus, which came to her with great intensity because she accepted suffering.
It disturbs me when I hear apologists make claims that God made what on some level was an arbitrary choice to have the world be harder than it really had to be. There is no evidence for this whatsoever, and it does no one any good who is suffering to hear that God could have eased it but for His own reasons doesn’t do so. That neither alleviates the suffering nor offers consolation, and if anything it is an impediment to the soul to draw closer to God. God did not “choose to” make the world any different than it had to be. God gave us His best, which is the best there could possibly be, by definition. We are living beings in a creation that sustains us. This is the result of an incredibly finely-balanced set of circumstances and of physical laws, none of which can be changed without throwing the whole system out of whack.