Jesus is the Light of the World. God uses the metaphor of light to display His perfect knowledge, purity and glory.

Jesus said to his desciples that the light is among you for a while, so walk in the light. He also stated, I am the light.  When it is dark we cannot see clearly and when the light is shown on something, all it's flows appear which you could not see in the dark.   We are walking in the dark, because we do not want other people to see our flaws.  We hide from them.   Jesus came into the world to change this.  We are all sinners and deserve death, but Jesus came and died on the cross to take on our sins and make us pure.  All we have to do is believe in him.  The light represents Heaven and the darkness represents Hell.  Jesus expects us to take the light that God word and Jesus has shown us and to spread it so that other people can see the light. This is the only way we can get to Heaven and see the Lord. 

We need to seek the Lord our God, with all our might and all our will and spread the light out unto the world with a humble heart.