A.C.Pike
Introduction
This post is not to glorify Satan in anyway whatsoever, but to show from Scripture that Satan is the evil ruler of this present world (age/system).
Kingdoms Of The World
In two of the synoptic Gospels (Matthew and Luke), we see Satan trying to tempt the Lord Jesus Christ (Chapter Four). In this temptation, Satan offers Jesus the kingdoms of this world if he will bow down and worship him (Matthew 4:8-10). If these kingdoms were not Satan's to give, then how could he offer them to Jesus?
After Jesus' ascension into Heaven (when he receives all power and authority), we read in the book of Revelation that the Dragon (Satan) "gave power unto the beast" (Revelation 13:4). This beast has ten horns on it's heads (Revelation 13:1). These horns are ten kings that rise up (Revelation 17:12). As we know, kings have to have kingdoms to rule over. So these horns are kings who reign over kingdoms.
Their (The Beasts And Kingdoms) Ruler
The Apostle Paul in his Second letter to the Corinthians calls Satan the "god of this world" (2 Corinthians 4:4), stating that Satan is the present ruler of this world (age).
In another letter, the Apostle Paul calls Satan "the prince of the power of the air" (Ephesians 2:2). The Greek reads "the ruler of the power of the air."
The Apostle John who wrote the book of Revelation, says that "the whole world lieth in wickedness" (1 John 5:19). The Greek word for wickedness can also be translated as "the evil one" (NKJV).
Jesus himself calls Satan the "prince of the world" (John 14:30), clearly stating that Satan is the ruler (prince) of the world (order).
As we can see from the above Scriptures, Satan is the "god" and "ruler/prince" of this present wolrd (fallen age/order).
The Sovereign Lord
I would like to say that the absolute ruler of the Heavens and the Earth is the only true God, Jehovah. It is he alone that is Universal Sovereign and Supreme Ruler of all things.
Notes
The first beast mentioned in Revelation 13 is the combining of the four major kingdoms (Babylon, Medo-Persian, Greece, and Rome) that Satan uses to attack Israel.
Scriptures
All Bible quotes taken from the AV/KJV Bible except for 1 John 5:19 where both the AV/KJV and NKJV are referenced.