In 1John 1:5 the author of this epistle sums up all that Jesus taught and presents it in the clearest of terms, so profound that the brightest of scholars are impotent to exhaust its revelation, yet so simple that the least perceptive of men could understand its meaning. John tells us that God is Light! He is not the Light or a Light, which would convey the idea that light was an attribute of God. Rather, God is Light, in that light is his essence. He reveals, he uncovers, he makes manifest all that is or ever could be. Immediately after the Lord created the heaven and the earth, and while darkness enveloped it all (Genesis 1:1-2), God said let there be light (Genesis 1:3). Without light, beauty couldn’t exist. Without light, life, itself, couldn’t exist. If one tried to define Light one might say it is perfection, purity, without flaw, all knowing (because it makes all that is manifest), immeasurably holy (because although it reveals all things, whether good or evil, it stands apart from all things).
Jesus came to reveal the Father, whom no man had ever seen, nor could see (John 1:18; 1Timothy 6:16). No one is able to see light, but light makes sight possible. Jesus, who is the Word (or Expression) of God, and is, in his essence, God (John 1:1), was made manifest in the flesh (John 1:14) in order to reveal the Father (John 1:18). Therefore, Jesus, in his essence (even while in the flesh), was Light in that he had made God manifest to man, while he (Jesus) lived out his life in the flesh. This is John’s summation of the message of the Gospel, which he received from Jesus (1John 1:5), namely that God is Light.
In the pagan culture we find that God is an unknown entity. He is someone who is feared, not loved. He is often depicted as a being of like passions as men, even with the possibility of death. He is worshiped in ignorance and clothed in darkness, sometimes requiring human sacrifice, sometimes satisfied with the blood of animals, but always unknown, illogical, and a shadowy kind of being. In contrast, John tells his readers that Jesus’ message is God is Light, and in him is no darkness at all.
John doesn’t try to say darkness doesn’t exist at all. Rather, no darkness exists in God. Physical darkness exists, but the Lord stands apart from it, for he is Light. Moral darkness exists, but, once more, the Lord stands apart from it, as well. Light dispels darkness, but we need to keep in mind that in his epistle John sums up the Gospel. He doesn’t try to reiterate it. His readers have his Gospel before them, as they read John’s letter and understand that the Kingdom of God is not something that one could locate on a map. It isn’t something they could point to and say, “it is here or there.” Rather, the Kingdom of God is within man (Luke 17:20-21). It is within the heart of man that darkness is dispelled by the Light.
According to John, Jesus said he was the Light of the world, and those who believed him would “not walk in the darkness, but will have the Light of life” (John 8:12). In other words, to walk in the Light requires faith, so if God, who is Light, would have any effect upon the darkness, men must believe. There are those who have the Light and are spiritually alive, and those who walk in darkness and are spiritually dead (cp. Ephesians 2:1-3). In other words, this is, in fact, the judgment that has already been pronounced upon this world, namely, “the Light has come into the world, and men loved darkness rather than Light, because their deeds were evil” (John 3:19). The Light makes everything manifest, but evil tries to hide its works (John 3:20). Nevertheless, those who love the truth don’t fear the Light, because the Light is what makes truth apparent, showing it (the Light) is of God.
Jesus had come from God, because he had both seen and known the Father (John 6:46; cp. 1Timothy 6:16). Therefore, it is only logical that he alone could reveal him (John 1:18). In this context, therefore, Jesus is Light (1John 1:5), in that he is God (John 1:1) manifest (John 1:14). To receive Jesus, therefore, is to receive the Father, whom Jesus had made manifest. To reject Jesus is to reject the Father (cp. John 5:23; 15:23-24), who has been made manifest in the Light (Jesus). John, however, doesn’t conclude that, now that the Father has been revealed, there is nothing more to say or understand about him. Rather, as the Light, Jesus has revealed God, and that knowledge of him is inexhaustible. It is there for us to understand throughout our lives, and eternal life, itself, is described as coming to know the Father through Jesus, whom he had sent (John 17:3).