Revelation 12:7-9 NIV

[7] Then war broke out in heaven. Michael and his angels fought against the dragon, and the dragon and his angels fought back. [8] But he was not strong enough, and they lost their place in heaven. [9] The great dragon was hurled down—that ancient serpent called the devil, or Satan, who leads the whole world astray. He was hurled to the earth, and his angels with him.