The Gospel of John is the Gospel of the light and the eternal life. Christ tells us "I am the Light." What is meant by "light" in the Bible?
When there is light we see the way, we walk, we have a guide. The light symbolizes the guidance of God that shows us the way in difficult situations.
God's guidance is an intuitive knowledge, about the present and the future that is traduce into clairvoyance and divination. It is important to understand that this should not be taken in a negative sense as spiritualism but in a positive sense since the source of this ability is the contemplative activity: "this is eternal life that they may  know you the only true God", John 17 :3.
In the Bible there are practical cases about the divine guidance: Joseph and the divination of Pharaoh's dreams in the book of Genesis, King Solomon asking God for a wise heart  in the book of Kings, the Magi who are warned by God when they find the baby Jesus in the gospels.
There is a teaching in the Gospel of John that adds knowledge about the Light:

If anyone walks in the day, he does not stumble,
because he sees the light of this world.
But if anyone walks in the night, he stumbles
because the light is not in him.
John 11:9-10

Those who walk in the day, are those who have Security or Trust in God, by that particular knowledge of the divine nature, do not stumble, they are free from error, from failure, from curse and disgrace. "To see the light", the spiritual enlighment in the Gospel of John means to contemplate God, that is, to enter into eternal life.
Recall that eternal life is a set of blessings that God gives in advance of the life in glory.
These blessings are contemplative activity, longevity or immortality, happiness of the heart and God's guidance.
Jesus is telling us that he is the "light", the "guidance of God". Remember that the Kingdom of God is the divine order of the things.
Then we can say that the kingdom of God has a double meaning. The man makes himself “son of God” that is to say the man lives the gifts (perfections) of God, and on the other side “God became son of man” that is to say the spiritual gifts and perfections of God are personified in Jesus.