Below is a copy of the article (from Chapter 20 of God's Plan For All, by David and Zoe Sulem) that prompted me to really start thinking outside the box ...

CALVINISM, ARMINIANISM and UNIVERSALISM

Do you profess to be a Bible believing Christian?  All Bible believing Christians fall into one of three categories of Christian beliefs, known as Calvinism, Arminianism and Universalism.  These are the three distinct and separate schools of Christian theology. With regard to salvation, every professing Christian inevitably falls into one of them, whether he understands or is aware of these terms or not.  So, if you claim to be a Bible believing Christian, after you remove all of your denominational clothing, you are a Calvinist Christian, or an Arminian Christian or a Universalist Christian.

Each belief system claims to be biblically based, and theologians have argued and debated the issues relating to them for centuries. However, the core differences between these three beliefs are irreconcilable.  There are five points in Calvinism, five points in Arminianism, and even five points in Universalism, which outline each of these belief systems.  It is not our intention to go into a detailed complicated theological analysis of each point in each belief system, but only to highlight and summarise the core differences between them.

Calvinism was the most dominant and widely held belief of Protestant Christians from the time of the Reformation for hundreds of centuries up until the last century.  Arminianism has now overtaken Calvinism by a long way, and currently most Christian churches are Arminian in their belief.  There is sufficient historical evidence to show that Universalism was the most widely held belief for the first five centuries, following the death of Jesus Christ.  However, this all changed when the Roman Catholic Church pronounced an anathema in 573 A.D. on anyone who believed in Universalism.  Currently,  Universalism is a very small minority belief of perhaps no more than 2% of Bible believing Christians.

What is Calvinism?
It is a system of theological belief promoted by a French man, John Calvin (1509-1564), and expressed in the document called Institutes of the Christian Religion.  Calvinism laid the foundation for the Reformed Theology of the Reformation period.  Calvinism is the basis for the doctrine of many Baptist, Presbyterian, Anglican and Reformed churches.  According to Calvin, before the beginning of the world, God predestined to save a certain group of people called God's Elect.  God's sovereign will for the salvation of His Elect cannot be resisted or thwarted, as His irresistible grace ensures that all of them will willingly accept Jesus Christ at some point in their lives before they die.  The non-Elect cannot come to Christ because natural fallen man is totally sinful and depraved.  Salvation is entirely the work of God from start to finish. All believers (the Elect) will go to heaven, but all unbelievers (the non-Elect) will be judged by God and cast into hell where they will be tortured forever. Chapter 20 – Calvinism, Arminianism and Universalism.

What is Arminianism?
It is a system of theological belief promoted by a Dutch man, Jacobus Arminius (1560-1609). Arminius started out as a strict Calvinist, but later changed his views as stated in the document called, 'The Remonstrance'.  Arminianism is the theological basis for Methodists, Wesleyans, Nazarenes, Pentecostals, Free Will Baptists, Holiness churches and many charismatic churches.  Roman Catholicism is also basically Arminian in its belief.  According to Arminius, Christ died for all people and God wills all men to be saved and come to the knowledge of the truth.  However, God's will can be frustrated and thwarted by man and God's grace can be resisted by man's freewill.  This is because it is left to each person to ultimately decide whether he wishes to be saved or not.   Therefore, in order to go to heaven each person must choose to accept Jesus Christ before he dies.  All those who die without choosing Christ will be judged by God and cast into hell, where they will be tortured forever.

What is Biblical Universalism?
Origen of Alexandria (185-254 A.D.) is the earliest Christian theologian known to have written about Universalism, the belief that eventually everyone will be saved through the work of the cross.  However, we do not believe that Origen had the full revelation of true Biblical Universalism.   According to the Bible, Jesus Christ died for the sins of the whole world, and He will reconcile all things in heaven and all things on earth to Father God through the blood of the cross because He is the Saviour of the world.  God is working out His plan of salvation for all people in ages, in His time and in His order.
God first saves His Elect, whom He predestined from the foundation of the world, to believe in Jesus Christ during this life before they die.  They are the firstfruits with Christ, only the few, called and chosen for a special purpose and a special salvation. God’s Elect Bride will rise in the First Resurrection at Jesus Christ’s Second Coming to enter the Millennial Kingdom with Him.  The glorious purpose of God’s Elect Bride, the firstfruits, is that after Jesus Christ marries her, there will be the Great Harvest of more fruits, birthed from this marriage.  The union of the Bride of Christ with Jesus Christ will bear multiple billions of spiritual children born into the Eternal Kingdom of God.  These spiritual children are none other than the rest of humanity who will rise in the Second Resurrection.
Ultimately, through God’s refining yet merciful Lake of Fire judgement, all unbelieving resurrected people, without any exceptions, will repent and believe in the full work of the cross through God given faith.  They will all freely and thankfully accept the gift of salvation and enter into the Eternal Kingdom of God of the New Heaven and the New Earth.  This subject is covered in detail in Chapter 12.

Which God are you serving?
The God of Calvinism sacrificed his son Jesus Christ to die on the cross for his Elect only, and he predestined only his Elect to be saved.  This must also mean that he predestined, knowingly and willingly, to cast the vast majority of humanity (the non-Elect) into hell to be tortured forever.  This makes the God of Calvinism an evil god, infinitely and unimaginably more evil than Hitler could ever be.

The God of Arminianism sacrificed his son Jesus Christ to die on the cross for all people, and he wills all people to be saved and come to the knowledge of the truth, but he has made himself helpless to save all people by allowing man's freewill to override his will in salvation.   Against his will, the God of Arminianism is forced to throw the majority of humanity into hell to be tortured forever because, for one reason or another, they failed to accept Jesus Christ in this life before they died.  Even worse than that, the God of Arminianism knowingly and willingly created human beings, with full foreknowledge that the vast majority of them would reject salvation and end up being tortured in hell forever.  This makes the God of Arminianism both an evil god, as evil as the God of Calvinism, and a weak god who allows Satan and sinful men to override his will in salvation.

The God of the Bible sacrificed His son Jesus Christ to die on the cross for the sins of the whole world. He died for all people; past, present and future, and He wills all people to be saved and come to the knowledge of the Truth. He has unlimited wisdom, power and love to save all people in His time and in His order. Ultimately, all people will freely and thankfully accept the gift of salvation in this life or the next life, and be reconciled to God through the finished work of Jesus Christ on the cross. This makes the God of the Bible a Good Father God who is all-powerful, all-loving, wise, just, merciful, gracious and forgiving.

Conclusion
Make no mistake about it, you are profoundly affected by how you understand these three belief systems: Calvinism, Arminianism, and Universalism.  Your understanding of God's sovereignty, His love, His justice, His righteousness, His grace, His forgiveness, and above all the full work of the cross, are all fundamentally governed and coloured by each belief system.  People who believe that God will punish unbelievers in hell forever or annihilate them limit God’s sovereignty, power, love, grace, forgiveness and the very Gospel of Jesus Christ.  They deny that Jesus Christ is indeed who He says He is, the Saviour of the world.