Throughout this section the Pharisees are trying to trap Jesus into saying something against Rome or against the Law and  Jesus is explaining who He is. While the Israelites were wandering in the desert they were led by God with a pillar of fire by night to light the way in the darkness. In Isaiah 42 the Messiah is described as a “ light to the Gentiles”  Jesus is saying “I am that light that led you in the wilderness darkness.”  “I am that light that will be for the Gentiles.”  Jesus the Great “I Am” is the light for the whole world.