In this verse, it is unfortunate that mankind did not respond well to Jesus' light during the dark time. The world did not understand Jesus, His teachings, gospel, and revelation. The inability to see Jesus for who He is is mostly a result of a person's stubbornness and foolish pride rather than his intellect.
It is true that God is Spirit, but Christ came to earth as a mortal man to be our Savior. Men can only receive peace with God and the peace of God through the Man, Christ Jesus. There is only One who can bring hope, joy, and eternal life because God the Father decreed that the Son would come to shine the light of God's life and love into the world. All who believe in Him may be illuminated by the truth, enlivened by the light of His love, and enlightened by His life.
Christ has been shining as the light of the world since eternity past. The light of God, life, and love can only be emitted through Him, for God has decreed that He is all in all. For the ages to come, may we bathe in the glory of His love and reflect that light to those around us in this darkened world.

Dear Heavenly Father, thank You that the light of Jesus has shone into my heart, for I trust Him alone as my Savior and Lord. Father, please illuminate the world so that darkness cannot overcome it. Please open the hearts of these stubborn and arrogant souls. May the light of Your love shine through me to others, for Your praise and glory, for I am nothing and You are everything. 
In Jesus's name I pray. Amen.