Remember, God did not spare angels when they sinned, but sent them down to Tartarus, and committed them to caverns of darkness, to be kept under guard for judgment.
and that even those angels, who did not keep to their appointed spheres, but left their proper homes, have been kept by him for the judgment of the Great Day in everlasting chains and black darkness.
Then I saw another mighty angel, descending from Heaven. His robe was a cloud; over his head was the rainbow; his face was like the sun, and his feet like pillars of fire;
He flung him into the bottomless pit and locked it, and set his seal upon it; that he should not deceive the nations any more, until the thousand years were ended. After that he must be let loose for a while.