And war broke out in heaven, Michael [the archangel] and his angels waging war with the dragon. The dragon and his angels fought, but they were not strong enough and did not prevail, and there was no longer a place found for them in heaven.
And the great dragon was thrown down, the age-old serpent who is called the devil and Satan, he who continually deceives and seduces the entire inhabited world; he was thrown down to the earth, and his angels were thrown down with him.
Then I heard a loud voice in heaven, saying:
And they overcame and conquered him
by the BLOOD of the LAMB
Word of their Testimony,
For they did not Love their life
They did not renounce their faith even when faced with Death.
Therefore rejoice, O heavens and you who dwell in them
Woe to the earth and the sea, because the devil has come down to you in great wrath,
knowing that he has only a short time [remaining]!”
Taken from Revelation 12 (Amplified Bible)