Christ's words in Revelation 2:12-17, is addressed to the locally assembled church in the geographic place called Pergamum: a place of Satan's seat. There we have heard Christ's words, which contain a warning about idolatry, Satan's plan of false worship.
From those early days after Creation, when Adam sinned and all of mankind to follow also fell into sin, God made a way for mankind to come back. The way back was to worship Him by a substitutionary, sacrificial, blood-sprinkled way.
The key to understanding all of world history since the Fall of Humanity into sin comes from God's Word. Always remember that the only absolutely trustworthy and accurate account of the earliest days of both the Universe and the human race is found in the inspired words from God in Genesis.
As we turn back to Genesis 4 we are seeing the very first description of the deadliest evil humanity has ever faced. It is called Religion.
Religion is mankind offering any kind of worship to God, other than what God's Word has commanded. Religion is the self-styled offering of a humanly designed worship, rather than the Spirit-prompted offering of strict obedience to God's Word.
That means that there are only two choices in the Universe, for offering true and acceptable worship: God's revelation of what He wants in His Word, and everything else. Here is point number one:
Satan Always Counterfeits God's Plan
When Satan as the Serpent in the Garden tempted Eve, he made her question whether God's plan was best. Satan always offers his own plan, a counterfeit that is meant to derail humans from what has been revealed in the Word of God.
In the account of Cain & Abel we find the first appearance of Satan's plan to destroy the true worship of God after the Fall. It is so clearly seen in the contrast between Cain's response to God's command for worship and Abel's response. Satan started a plan to counter God's true worship, and Cain was his first convert.
Genesis 4:8 is what we could call the start of religion: Mankind trying to make his own way to worship God by self-effort. Cain decided to give God what Cain felt like offering, not what God wanted. In fact the inspired commentary from God about Cain's life says:
1 John 3:12 (NKJV) not as Cain who was of the wicked one and murdered his brother. And why did he murder him? Because his works were evil and his brother's righteous.
Also the next book after John's Epistles, called Jude, also has similar warnings:
Jude 1:11 (NKJV) Woe to them! For they have gone in the way of Cain, have run greedily in the error of Balaam for profit, and perished in the rebellion of Korah.
Cain's life is forever tied to one of the most dramatic moments in sacred history. Genesis 4:1-8:
Genesis 4:1-8 (NKJV) Now Adam knew Eve his wife, and she conceived and bore Cain, and said, "I have acquired a man from the LORD." 2 Then she bore again, this time his brother Abel. Now Abel was a keeper of sheep, but Cain was a tiller of the ground. 3 And in the process of time it came to pass that Cain brought an offering of the fruit of the ground to the LORD. 4 Abel also brought of the firstborn of his flock and of their fat. And the LORD respected Abel and his offering, 5 but He did not respect Cain and his offering. And Cain was very angry, and his countenance fell. 6 So the LORD said to Cain, "Why are you angry? And why has your countenance fallen? 7 If you do well, will you not be accepted? And if you do not do well, sin lies at the door. And its desire is for you, but you should rule over it." 8 Now Cain talked with Abel his brother; and it came to pass, when they were in the field, that Cain rose up against Abel his brother and killed him.
Cain and Abel portray the eternal truth that there are:
Only Two Choices, Only Two Destinations
Two lines run through the history of mankind: the line of Christ and the line of Antichrist, the line of the Woman's seed and that of the serpent.
So, there are only two groups of people always on Earth, and they are heading to very different destinies:
- The Way of God-Followers: like Abel's example, they kneel before a substitutionary, blood sacrifice pointing at Golgotha, and justified by faith, they go to Heaven.
- The Way of Satan-Followers: like Cain, they kneel at the altar of their good works pointing at Babel, and condemned by their own sins, they go to the Lake of Fire.
There are only two families that everyone is a part of: (God's or Satan's); there are only two destinies that are ahead of every human that has every lived: (Heaven or Hell); and life is really reduced to only one or the two choices: (repent or reject). Each of us today belongs to one family or the other. You are choosing your own future.
Here in Genesis 4 we see that Cain and Abel are not only two actual people who lived and walked on earth a few thousand years ago. They also represent the two roads that head out from the Garden of Eden. Everyone who has ever lived has chosen one of those two paths. Each of us are on one path or the other.
Watch the choices made by Cain and Abel. Both were born outside of Eden. Both were sinners and fallen. Both were lost and guilty of each sin they had committed. Neither were innocent, but only Abel would confess that! That is what:
Genesis 4 Contrasts: Satan's Followers (Cain) vs. God's Followers (Abel)
To help us understand the magnitude of this doctrinal lesson that Cain and Abel portray, we need to look at their lives, and the lessons from those lives, one at a time.
First we can see:
Satan's religion: The Wicked Way of Cain
- Cain neglected God's example of a bloody substitute for covering sinners, and got angry when God corrects him.
- Cain portrays a salvation based on human merits-the natural, self-righteous, self-sufficient and lost person; the formal, external-only professors, who are trusting their works.
- Cain was rejected and cursed by God; denied his lost ruined condition, refused the Divine remedy, and became a merely religious, but lost person.
- Cain looked for help from within himself to please God; he makes an un-bloody offering, and ignores the curse removing, substitutionary, blood sacrifice offered by Abel.
- Cain was the father of all those who seek earthly security and those that God calls "Earth-Dwellers".
- Cain turned from the true altar of worship to God, ignored the message and founded the first earthly city (Genesis 4:17).
God's revelation: The Righteous Faith of Abel
- Abel followed God's example and offered a bloody substitute as an offering for sinners; he humbly gave God what He asked for.
- Abel portrays a salvation only by Divine grace-the Spiritual Person, who is broken-spirited, taking God's side against themselves; the saved, genuine believer and possessor of faith in Christ's finished work alone.
- Abel was accepted and blessed by God; he acknowledged his personal sins; he believed God's testimony, placing faith in the substitute and was accounted righteous, and was a genuinely saved person.
- Abel looks for help from outside himself to please God; he makes a bloody offering, and trusts the curse removing, substitutionary blood sacrifice he offered.
- Abel was the father of all those who seek God as their refuge, and those that God calls Citizens of Heaven.
- Abel came to the true altar of worship to God, heeded God's message, and founded a grave stained with blood on his way to the heavenly city.
The ways of Cain and the faith of Abel go on until the time of the Global Flood of Noah.
But notice that there is no mention of any idolatry in these early chapters of human history, until after the Flood. Sin was so bad, humanity was so corrupted, and the demons had made such complete inroads in humanity, God said, that's it.
Turn in your Bible past those days recorded in Genesis 5-8, where God wipes out everyone but the eight in Noah's family. But as we do so, remember:
God Destroyed the Whole Earth in the Flood
In Genesis 7:21-23, note that God's Word says that every human and air-breathing animal not on the Ark was killed in the Flood. That was not a local flood as some try to make it. You may want to mark some of these words in your Bibles as you follow along.
Genesis 7:21-23 (NKJV) And all flesh died that moved on the earth: birds and cattle and beasts and every creeping thing that creeps on the earth, and every man. 22 All in whose nostrils was the breath of the spirit of life, all that was on the dry land, died. 23 So He destroyed all living things which were on the face of the ground: both man and cattle, creeping thing and bird of the air. They were destroyed from the earth. Only Noah and those who were with him in the ark remained alive.
Moving on, God gives mankind a fresh start in learning how to seek Him correctly in Genesis 8:20. There God is worshipped in the true and proper way by the substitutionary, blood sacrifice upon an altar. Note the re-affirmation with the family that would restart humanity upon the Earth. God says to Noah:
Worship God First, Worship His Way
The very first thing as soon as they landed, the ground dried and the ark was emptied: was a bloody, substitutionary sacrifice on an altar, the way God asked for it to be done. Follow along with the words God gives us:
Genesis 8:18-22 (NKJV) So Noah went out, and his sons and his wife and his sons' wives with him. 19 Every animal, every creeping thing, every bird, and whatever creeps on the earth, according to their families, went out of the ark. 20 Then Noah built an altar to the LORD, and took of every clean animal and of every clean bird, and offered burnt offerings on the altar. 21 And the LORD smelled a soothing aroma. Then the LORD said in His heart, "I will never again curse the ground for man's sake, although the imagination of man's heart is evil from his youth; nor will I again destroy every living thing as I have done.
22 "While the earth remains,
Seedtime and harvest,
Cold and heat,
Winter and summer,
And day and night
Shall not cease."
Just a side note: The Ark pictures salvation in many ways: God invited them in; only one door; those inside were saved by an atoning covering of pitch on the outside of the wooden ark (kaphar = atone); and all inside made it safely to the end.
The Ark Portrays Eternal Security
Genesis 7:16 & 8:19
Look at Genesis 7:15-17.
Genesis 7:15-17 (NKJV) And they went into the ark to Noah, two by two, of all flesh in which is the breath of life. 16 So those that entered, male and female of all flesh, went in as God had commanded him; and the LORD shut him in. 17 Now the flood was on the earth forty days. The waters increased and lifted up the ark, and it rose high above the earth.
Now look again what we just read in Genesis 8:18-19
Genesis 8:18-22 (NKJV) So Noah went out, and his sons and his wife and his sons' wives with him. 19Every animal, every creeping thing, every bird, and whatever creeps on the earth, according to their families, went out of the ark.
The Ark is a picture that all who come Christ's way of salvation (the one door) are kept safely to the end, and arrive safely home!
But skip over chapter 9, the rules for humanity (end of vegetarianism, start of capital punishment by government); and the covenant in the rainbow as a sign of God's mercy. Go with me to:
Genesis 10: The Mighty Nimrod, Founder of Babel
Genesis 10:8-12 introduces us to one of the most influential figures in the new world after the Flood of Noah.
Genesis 10:8-12 (NKJV) Cush begot Nimrod; he began to be a mighty one on the earth. 9 He was a mighty hunter before the LORD; therefore it is said, "Like Nimrod the mighty hunter before the LORD." 10 And the beginning of his kingdom was Babel, Erech, Accad, and Calneh, in the land of Shinar. 11 From that land he went to Assyria and built Nineveh, Rehoboth Ir, Calah, 12 and Resen between Nineveh and Calah (that is the principal city).
Satan had already begun in Genesis 10 to counterfeit what God would do. What we can see as we study this passage is that Nimrod was the human mind behind the first system of false religion. Nimrod founded a city called Babel/Babylon and it was the home of the beginnings of idolatry.
Nimrod was a grandson of Ham, which makes him a great grandson of Noah. He was the apostate of the patriarchal age. Idolatry began in Babel, according to God's Word. Mankind built the first object to be worshipped in place of God, which was the Tower of Babel. He established false worship.
The following details are what you can read in the commentaries of the following great Bible teachers: James Boice of 10th Presbyterian of Philadelphia; Harry Ironsides of Moody Church; John MacArthur of Grace Church; Harold Wilmington of Liberty University; John Wesley, founder of Methodism; and J. Dwight Pentecost of Dallas Seminary to name just a few.
Secular history and tradition tell us that Nimrod married a woman who was as evil and demonic as he was. Her name was Semerimis. Knowing God's promise of a future Savior (Gen. 3:15), Semerimis brazenly claimed that Tammuz, her first son, fulfilled this prophecy.
Building on the primeval promise of the woman's Seed who was to come, Semiramis bore a son whom she declared was miraculously conceived, and when she presented him to the people, he was hailed as the promised deliverer. This son was Tammuz, whose worship centuries later, Ezekiel protested against in the 6th Century BC days of the captivity.
Thus was introduced the mystery of the mother and the child, a form of idolatry that is older than any other known to man. The rites of this worship were secret. Only the initiated were permitted to know its mysteries.
It was Satan's effort to delude mankind with an imitation so like the truth of God that they would not know the true Seed of the woman when He came in the fullness of time. To this scholars as early as the 2nd Century Justin Martyr bear definite witness. 
Move on to the next chapter where we find:
Genesis 11: Babel's Tower, Babylon's Mysteries & Organized Religion
Satan's plan began to be exported globally at the tower of Babel in Genesis 11:1-9 which was the advent of what we would call Organized Religion. This was over 24 centuries before Christ, and nearly 4,500 years ago.
The Tower was the first idol and it became the object of men's worship, the point of their pride. It spawned a complex of weird, strange, mysterious religions that are still going on in our world today.
Genesis 11:1-9 (NKJV) Now the whole earth had one language and one speech. 2 And it came to pass, as they journeyed from the east, that they found a plain in the land of Shinar, and they dwelt there. 3 Then they said to one another, "Come, let us make bricks and bake them thoroughly." They had brick for stone, and they had asphalt for mortar. 4 And they said, "Come, let us build ourselves a city, and a tower whose top is in the heavens; let us make a name for ourselves, lest we be scattered abroad over the face of the whole earth." 5 But the LORD came down to see the city and the tower which the sons of men had built. 6 And the LORD said, "Indeed the people are one and they all have one language, and this is what they begin to do; now nothing that they propose to do will be withheld from them. 7 Come, let Us go down and there confuse their language, that they may not understand one another's speech." 8 So the LORD scattered them abroad from there over the face of all the earth, and they ceased building the city. 9 Therefore its name is called Babel, because there the LORD confused the language of all the earth; and from there the LORD scattered them abroad over the face of all the earth.
Remember that Satan want to counterfeit, confuse and mess up God's plan. So the one-world plans Satan had at Babel, God confounds, but Satan just sends out the great invasion of false worship, mystery religions and idolatry from Babel to the ends of the earth.
Pagan Religions Originate from Babylon
The Gospel of Satan is religion, and he has made sure that it has gotten to every corner of the Earth. At the Tower of Babel's worship ziggurat, the Babylonian Mystery Religions fill the pages of ancient history. They're all over everywhere and they're still with us today all in different forms. 
There, on the fertile plain of Shinar, probably not far from the original Garden of Eden, the first spade of dirt was turned for the purpose of organizing humans into Creator-rejection and Devil-worship.
Alexander Hislop, the great 19th century Scottish theologian and historian traced the concept of false religions under the idea of Babylonianism. After God destroyed the tower, He scattered mankind into multiplied language groups. Semaramis was worshiped as a goddess under many different names.
She became Ishtar of Syria, Ashtaroth of Phoenicia, Isis of Egypt, Aphrodite of Greece, and Venus of Rome-in each case the deity of sexual love and fertility. According to the cult of Ishtar, Tammuz was conceived by a sunbeam, a counterfeit version of Jesus' virgin birth.
Tammuz corresponded to Baal in Phoenicia, Horus in Egypt, Eros in Greece, and Cupid in Rome. In every case, the worship of those gods and goddesses was associated with sexual immorality. The celebration of Lent has no basis in Scripture, but rather developed from the pagan celebration of Semiramis's mourning for forty days over the death of Tammuz (cf. Ezek. 8:14) before his alleged resurrection-another of Satan's mythical counterfeits.
Now, that means that Babel, became the fountainhead of all false religion. That's why when false religion reaches its climax in the end times, God's Word calls false religion by the name of Babylon again inRevelation 17-18.
 Adapted from Wilmington's Guide to the Bible, in loc.
 Henry Allen "Harry" Ironside (October 14, 1876-January 15, 1951) was a Canadian-American Bible teacher, preacher, theologian, pastor, and author. Found also on Lambert Dolphin's site at:http://ldolphin.org/semir.html This article copied from:http://www.biblelineministries.org/articles/basearch.php3?action=full&mainkey=BABYLONIAN+RELIGION+%28By+Harry+A.+Ironside%29
 John MacArthur preached this in a Mother's Day message on 5/14/72
 Adapted from Two Babylons quoted by MacArthur in Acts and I Corinthians. (For a discussion of the relationship of the pagan mother-child cults to Roman Catholic teachings about Mary, see Alexander Hislop, The Two Babylons [Neptune, N.J.: Loizeaux, 1959].)