Jesus is the radiant light of the entire world. Three things to help us see this:
1. John the Baptist gave off light (6-8)- John only came to testify, and people thought he was the Light! How much brighter is the Light!
2. The Light got brighter than it already was (9)- The light was in the world, but the Light was coming into the world in a new way, to be even brighter!
3. But the Light had been bright enough (10-13)- The Light was rejected as a whole, but was still bright enough to save some, whether it was Abraham or Rahab or Josiah.
But the beauty of verse 9 is that even though the Light was bright enough to save, the true light that gives light to every man still came into the world to be even brighter!