Concerning the Nature of Good, Against the Manichaeans

But because evil angels also were not constituted evil by God, but were made evil by sinning, Peter in his epistle says: "For if God spared not angels when they sinned, but casting them down into the dungeons of smoky hell, He delivered them to be reserved for punishment in judgment." Hence Peter shows that there is still due to them the penalty of the last judgment, concerning which the Lord says: "Go ye into everlasting fire, which has been prepared for the Devil and his angels." Although they have already penally received this hell, that is, an inferior smoky air as a prison, which nevertheless since it is also called heaven, is not that heaven in which there are stars, but this lower heaven by the smoke of which the clouds are conglobulated, and where the birds fly; for both a cloudy heaven is spoken of, and flying things are called heavenly. As when the Apostle Paul calls those evil angels, against whom as enemies by living piously we contend, "spiritual things of wickedness in heavenly places." That this may not be understood of the upper heavens, he plainly says elsewhere: "According to the presence of the prince of this air, who now works in the sons of disobedience."