Human history has often confused false light with proper illumination, but Scripture makes clear that only God gives light that leads to life. He calls His people out of darkness into marvelous light, empowering us to shine as witnesses in a world overshadowed by spiritual blindness.
The darkness mentioned in verses 5 and 6 is the universal symbol and condition of sin and death. In direct contrast, light mentioned in verse 7 is the symbol and expression of holiness. God, by His presence and grace, is to His holy priesthood and His holy nation as a marvelous light.
If God and His Son are light, then light also symbolizes salvation and new life. The individual who does what is true comes to the light, so that it may be clearly seen that his deeds have been done in God.
So when Jesus spoke of Himself as the light of the world, those who follow Him are described as people who will not walk in darkness, but will have the light of life. According to I Peter 2:9, God's own special people are those who have been called out of darkness into His marvelous light. And when light exposes something, it becomes illuminated because anything that becomes visible is light, as Paul explains in Ephesians 5:8.
