The account of Satan's (Lucifer's) rebellion and fall from heaven with all his followers takes up a major portion of the plot of Paradise Lost. The Biblical sources of this occurance are brief, but early church writings had fleshed out these lines by the time Milton began composing his epic.

THE BIBLE: King James Version

Isaiah XIV

12 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!
13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north:
14 I will ascend above the heights of the clouds; I will be like the most High.
15 Yet thou shalt be brought down to hell, to the sides of the pit.

Revelation XII

4 And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.

7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.

THE BIBLE: Contemporary English Version

Isaiah XIV

12 You, the bright morning star, Lucifer, have fallen from the sky! You brought down other nations; now you are brought down.
13 You said to yourself, "I'll climb to heaven and place my throne above the highest stars. I'll sit there with the gods far away in the north.
14 I'll be above the clouds, just like God Most High."
15 But now you are deep in the world of the dead.

Revelation XII

4 With its tail, it dragged a third of the stars from the sky and threw them down to the earth. Then the dragon turned toward the woman, because it wanted to eat her child as soon as it was born.

7 A war broke out in heaven. Michael and his angels were fighting against the dragon and its angels.
8 But the dragon lost the battle. It and its angels were forced out of their places in heaven
9 and were thrown down to the earth. Yes, that old snake and his angels were thrown out of heaven! That snake, who fools everyone on earth, is known as the devil and Satan.