Revelation 9:15

And the four angels were loosed. This seems to indicate the moment in which Satan himself is loosed from the abyss or hell, where, as we shall see [in] Apocalypse xx. 2. he was chained up for a thousand years. This is the time of antichrist, whose coming, as St. Paul says, is according to the working of Satan. (2 Thessalonians ii. 9.) The antichristian period is described by the ancient Fathers as the most dreadful of all; and the Apocalypse plainly shews it to be so, as we shall see. But we have this comfort, that his time will be short. He must be loosed a little time. (Apocalypse xx. 3.)