BaB BaB BaB Revelation 12:10-11.
Revelation 12:9-12
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.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
12 Therefore rejoice, ye heavens, and ye that dwell in them. WOE to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
The short time will be the 42 months reign of the Beast mentioned in Revelation 13 when Satan[the Dragon] AND The Beast/AC AND the False Prophet will reign over the Earth.
God allowed Satan to Enter the Garden of Eden to tempt Adam and Eve ..God wanted to see whom Adam and Eve will follow... with the consequence that Satan became the Prince of this World --- Sin and Death .
Do you remember that God was temporary absent at that moment Genesis 3.