The answer
There are about 100 verses about the devil, his existence, and his tricks mentioned in the Holy Scripture. http://www.openbible.info/topics/satanThe Holy Book of Revelation is the most difficult Scripture to interpret. Some of the events have already passed, some are current in our times, and some are prophetic—yet to come. Some commentaries explain that the woman mentioned in Chapter 12 is the persecuted Church and the dragon is the heathen Roman Empire. The reason of the illustration of a dragon is because it is symbolic of paganism and mythology and captures their idolatry of faith and their immense political and social power—having multiple horns alluding to other powerful kingdoms and empires.
Reference:
http://biblehub.com/commentaries/clarke/revelation/12.htm
Answered by His Eminence Metropolitan Youssef (opens in a new tab)