John 12:46-47 I have come as a light into the world, that whoever believes in me may not remain in the darkness. 47 If anyone listens to my sayings, and doesn't believe, I don't judge him. For I came not to judge the world, but to save the world.
Jesus is the Lumination of the knowledge of God to the world. When we share Jesus we are in that Light, when we are at church we are in the Light, when we talk about Jesus we are in the Light. Sharing the Gospel is in the Light, the Light of God.
Our Believing in the Gospel, Believing in Jesus our Saviour, keeps us in the Light. We Christians have walked out of the darkness of sin, and ignorance about God into the marvelous Light, the lumination of the knowledge of God. Not only of God, but about our Righteous God, about who He is and how much God Loves us.
If anyone rejects Jesus, they are choosing to remain in their sin hidden by their own darkness.
God sees all, and Jesus has come to free them from the darkness that imprisonod them in their own sin. God will only shine the Light of His invitation on the sinner for so long. When the sinner's heart has become hardened to that point, God will give the sinner over to their hard heart, to their sin.
At that point there is no more hope for that person. They will die in their sin. Their future will be in the lake of fire with satan and all the others who have chosen the darkness of their sin, rather than a Life in Light with the Father God, Jesus our Lord, and the Holy Spirit our Companion.
