Jesus continues his metaphor about light and darkness in John 12. In the context of explaining to the crowds at the Passover feast about his impending death, Jesus says “the light is among you for a little while longer. Walk while you have the light, lest darkness overtake you… believe in the light, that you may become sons of light.”
Later, Jesus said “I have come into the world as light, so that whoever believes in me may not remain in darkness”. Darkness is not just the opposite of light, it is the absence of it. Without the light of the gospel message, we are without hope, without understanding of the future, as Jesus also points out, “The one who walks in the darkness does not know where he is going”.
Paul picks up on some of these ideas, exhorting the Ephesians to “walk as children of light”, since they were “at one time you were darkness, but now you are light in the Lord”. As children of light, our future is clear. It is up to us to share that hope with those around us.