What's the relationship between the invocation of light in book 3 and Satan's speech to the sun on Mount Niphates in book 4?

Satan lands on Mt. Niphates and has some moments of doubt. The light from the sun reminds him of the light and grace he had in heaven. He questions whether he would have fallen or not if he had been created by God with less pride in the first place. Being created from the beginning with a nature that would lead to his fall makes him hate God all the more.