"Amid the darkness which everywhere presses upon us, God is the lamp of His people, the source of their comfort and gladness." (The Preacher's Homiletic Commentary) The Apostle John gave us the sum of what they heard from Jesus' preaching - the sum of all that He said. That "message" was - "God is light, and in Him is no darkness at all." Jesus is the "Light of the world." He also is the God Who "shows His people light in their darkness."