Book III opens with a prologue, often called "The Prologue to Light," that is addressed to the "holy light" of God and Heaven. In this prologue, Milton asks for God's light to shine inwardly so that he can reveal what no man has seen.
Following the prologue, Milton reveals God, the Son (Jesus), and the Heavenly Host in Heaven. God looks toward Earth and sees Satan approaching the home of Man. A council takes place in Heaven. This council is mainly made up of a discussion between God and the Son on how Man will respond to Satan's wiles and what the ultimate resolution will be. God says that Man will be corrupted by Satan's treachery but that the evil will redound to Satan himself.
Man's failure to resist temptation will, however, be Man's fault since God has provided Man with both the reason and the will to resist these temptations. Nevertheless, because the fall of Satan and the other rebellious angels is worse than Man's (the angels fell because of personal failures; Man will fall only because of outside forces), God will offer Man mercy through grace. God adds, however, that unless someone is willing to die for Man, Man will have to face death: Divine justice requires that penalty for Man's transgression. The Son says that he will suffer death but also overcome it and, through this sacrifice, redeem Man from Man's sin.
The scene of Book III now shifts from Heaven to Satan who has landed on the border between Earth and Chaos. From this seat in darkness, Satan sees a light and moves toward it. The light is a golden stairway leading to Heaven. From this new vantage point, Satan views the magnificence of the Earth and of the beautiful sun that illumines it. As Satan moves toward the sun, he sees the archangel Uriel and quickly transforms himself into a cherub. Satan deceives Uriel and asks where Man may be found. Uriel directs Satan toward Earth.
