God gave John revelation of Satan's activity, especially during the Great Tribulation. He did so to enable his readers to understand better the reasons for and the forces behind the events of this strategic period of history.
"The method of narration beginning at this point differs from anything previous, because it focuses on the secret maneuvers that lie behind the visible conflict to be portrayed under the seven bowls . . . That future struggle is merely the outworking of a conflict between God and Satan that has lasted throughout history since Satan's fall. This prepares the way for all that is anti-Christian to enter the world at 13:1."388
Many ancient civilizations had myths that resemble this story.389