I John 1:5-2:2
Light represents what is good, pure, true, holy, and reliable. Darkness represents sin and evil. To say “God is light” means that God is perfectly holy and true, and that he alone can guide us out of the darkness of sin. Light is also related to truth, in that it exposes whatever exists, whether it is good or bad. In the dark, good and evil look alike; in the light, they can be clearly distinguished. Just as darkness cannot exist in the presence of light, sin cannot exist in the presence of a holy God. If we want to have a relationship with God, we must put aside our sinful ways of living.