We are in darkness until illumined by the Holy Spirit. Nature's darkness lets us see little further than the shadow we cast; without the light of life we do not know the way our path will take.
The promise is that God will turn our darkness into light. The light of the world must dispel the darkness. In the dark it is the ear that hears the gospel: not able to see, it is faith that reaches out and receives.
Repentance is a turning towards God; a turning towards the light that makes all light. Darkness must flee for it cannot remain when the light shines. The Creator who said 'Let there be light' stands ready to let His glory shine into our hearts.
'Shine, Jesus shine' is not a hope but a reality.