Naturally speaking, the world is in the darkness of sin,
ignorance, and aimlessness. The light of the world is Jesus.
Apart from Him, there is no deliverance from the blackness of
sin. Apart from Him, there is no guidance along the way of life,
no knowledge as to the real meaning of life and the issues of
eternity. Jesus promised that anyone following Him would not
walk in darkness, but have the light of life. To follow Jesus
means to believe on Him. Many people have the mistaken idea that
they can live as Jesus lived without ever being born again. To
follow Jesus means to come to Him in repentance, to trust Him as
Lord and Savior, and then to commit one's whole life to Him.
Those who do this have guidance in life and clear and bright
hope beyond the grave.
MacDonald, Believer's Bible Commentary