For the most part, when you step into a church they have many foundational beliefs in common when it comes to how to attain salvation. Beyond that point is where many churches differ. Many churches start out with the same beliefs taught in the Bible, but over time have strayed into adopting beliefs that are clearly contrary to the Bible. In Christian circles, two groups of churches that differ from one another are those who have adopted Reformed Theology, or Calvinism, and those who have adopted Arminian theology, sometimes called Methodism. On the surface, both believe the same thing when it comes to the need to trust Christ as their Savior for salvation, but beyond that is where the differences become stark in comparison. How do we know then, which theology is right, Reformed Theology or Arminianism? As always, the Bible provides the answer.
Are differences in theology new?
It is no secret that many churches have clearly apostatized from the truth of Scripture. A few years ago I saw a sign outside a notoriously liberal church entitled, “The compassion of abortion.” Not long after, I had the opportunity at a funeral to speak with someone who attended that church and I asked her if she was at the service when that message was delivered. With enthusiasm and assuming that I shared her views, she breathlessly praised her pastor as a woman who really speaks to her and guides her when it comes to women’s issues. She continued by telling me all the same old tired arguments for abortion like ending the enslaving of women, child abuse, and delivering a child from a life of poverty. I asked if since the U.S. Supreme Court decreed abortion to be a right if it has accomplished what it was supposed to do? Her response floored me when she said, “Not yet, there is much more work to do.” Unfortunately, we were unable to continue the conversation, but I wondered if over 50 million abortions did not solve the problems it was argued to solve, how many more children must die before this act of compassion had any effect?
Sadly, this is a common occurrence when it comes to differing beliefs. People stop following the teachings of Christ and start following the teachings of someone else. This is not something new. The Bible describes numerous times when people either did not know or strayed from the truth to follow the teachings of a person (Exodus 32; Judges 2:1-15; Acts 15; Acts 19:1-7; 1 Corinthians 1:9-17; 2 Corinthians 11:1-4). Likewise, the Apostle John described seven specific churches by name in the book of Revelation that had differing beliefs: Ephesus, Smyrna, Pergamos, Thyatira, Sardis, Philadelphia, and Laodicea. Only one, Philadelphia, did God not mention that He had anything against (Revelation 3:7-13). Yet, all of the churches were described as having amongst them those that overcome, which is a reference to being saved (1 John 5:1-5). It is no different today, many churches subscribe to theologies not totally in line with Scripture, yet there are still people in those churches that are overcomers in Christ.
What is the difference between Reformed Theology and Arminianism?
When it comes to the issue of salvation, both believe that salvation comes by God’s grace through faith apart from any works we may perform, no matter how good. However, there is a difference in the interpretation of Ephesians 2:8-9, “For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast.” The difference between these two groups is based on the identity of what “is the gift of God.” For the Calvinist, the gift of God is the faith needed for salvation. For the Arminian, it is salvation that God gives through our faith.
I have had many students diagram this verse to see what is referred to as “the gift of God” and it becomes quite clear. When diagramming this verse, the dependent clause, “that not of yourselves,” refers to something in the previous clause “For by grace are ye saved through faith”. We see that each noun in this previous clause, grace and faith, are part of prepositional phrases referring to salvation. These prepositional phrases, “For by grace” and “through faith” are directly describing how “are ye saved.” This is reinforced by the other three clauses: “It is the gift of God”, “Not of works”, and “Lest any man should boast. To believe otherwise would be saying that “not of works” is not referring to salvation, which goes against everything the Bible teaches about salvation! Likewise, faith comes by hearing and hearing by the Word of God (Romans 10:17).
Much more can be added, such as the fact that the nouns grace and faith are linguistically feminine in gender and the verb “saved” is not feminine. Likewise, the word “that”, used in the phrase “that not of yourselves” is not feminine. Since it is not feminine, it is not referring to a feminine object such as faith or grace. “That” can only be referring to salvation. This is in keeping with noun verb gender agreement in every language that uses it.
When it comes to the issue of eternal security, both believe in the concept of being eternally saved. However, Arminians place a condition on eternal security and Calvinists believe that if a person is truly saved, they are eternally secure in their salvation. For the Arminian, a person is saved by grace through faith, but can lose their salvation by works or give it up by choice. They use several verses out of context to come to this conclusion.
I have asked several who hold this belief what would cause them to lose their salvation and the response is consistently based on the believer falling into some sort of sinful lifestyle like adultery or drunkenness. When further pressed about lesser-perceived types of sins like telling a lie or an episode of unrighteous anger typically the response is that it probably would not result in a loss of salvation. This demonstrates a classic belief in mortal sins and venial sins common to Catholicism. When pressed on how a person gets their salvation back if they commit adultery or fall into drunkenness, the response is typically that the person must repent and stop committing adultery. Logically speaking, this suggests that salvation is by grace through faith the first time, but then after, it is by repentance and good works? God forbid!
To demonstrate this truth, I have asked people who make this claim that if what they are saying is true, then how many times a day did the Apostle Paul lose his salvation and get it back as the chief of sinners (Romans 7:14-25; 1 Timothy 1:15)? It is quite obvious in the light of Scripture that if we cannot earn our salvation by good works, what makes us think we have the power or are good enough to keep it or throw it away (Ecclesiastes 8:8; Ephesians 1:12-14; Ephesians 4:30; Hebrews 10:39; 1 Peter 1:3-9)? Furthermore, what gives us the right to tell the Lord that although He purchased us with His blood, we do not belong to Him anymore (Acts 20:27-28; 1 Corinthians 6:19-20; 1 Corinthians 7:23; 2 Peter 2:1)? If we are born again, how do we get unborn again? Do we become born again every time we get resaved?
Likewise, if we become a child of God by faith in Christ, do we stop being a child of God every time we lose our salvation (Galatians 3:26)? And, if this is so, do we stop being children of Abraham by faith and heirs to the promises that God made to him (Galatians 3:6-16)? Or, are we not sealed by the Holy Spirit of promise until the day of redemption, which is our non-refundable guarantee on our inheritance (Ephesians 1:12-14; Ephesians 4:30)? It is clear that this leads to so many questions that one could never have the assurance and peace that comes from knowing that God will never forsake them or leave them; that no man, including ourselves, can pluck us out of God’s hands (Ecclesiastes 8:8; John 10:28-29; Hebrews 13:5; 1 John 5:13). This leads to nothing but confusion.
There are many more comparisons that can be made, but it simply comes down to this. God knew in eternity past, who would trust Christ as their Savior and who would not (Romans 8:28-35). He knew that there are some people that no matter what you say or what they go through in life, they will never see the need for a Savior. Therefore, those whom He foreknew would love Him (believe the gospel), God predestined to be conformed to the image of His Son, meaning that God would set in motion the events that are needed so that we would hear the gospel at just the right time on our lives when He knew we would believe it. And, those who believe it will one day stand before God, perfect, conformed to the perfect likeness of His Son Jesus. This is what it means to be of the elect, those chosen by God based on His foreknowledge of who would or would not ever believe the gospel. Then, when we trust Christ, we are grafted into the elect family of Abraham, Israel, and made rightful heirs to His promises (Isaiah 45:4; Isaiah 65:9; Luke 18:7; Romans 11:16-17; Colossians 3:12; 1 Peter 1:2).
So, which theology is right?
As mentioned earlier, there were seven churches mentioned in the Book of Revelation. Only one was mentioned as God not having anything against, Philadelphia. When answering this question, we must look at how God described the believers in this local church in Scripture (Revelation 3:7-13). They believed that salvation was available to anyone. They believed that their strength was not of themselves, but of the Lord. They focused on learning and keeping God’s Word. And, did not forsake God’s name.
As a result, God promised them that He would have others look to them as being holy and loved by God. Because of their patience, He promised them that they would be kept from temptation. Finally, He promised the believers that He would make them a pillar, or a key foundational element in His temple and give them a new name as overcomers. With these things in mind, we must look to God’s Word to sort out differences in any theological construct made of men. When we can do this, then we can fully understand that following the teachings of Christ is never to be compromised by following the theological teachings of man (1 Corinthians 1:10-24). Therefore, we must conclude that only the teachings of Christ are right.
Churches have many foundational beliefs in common when it comes to how to attain salvation. Beyond that point is where many churches differ. Differences in theology are not new. Two groups that differ in theology are those who subscribe to Reformed Theology and Arminianism. They agree that salvation is by grace through faith, but differ on how that comes about. Likewise, they differ on Who or whom has the power to keep their salvation which results in confusion on many theological levels. When it comes to disagreements on theology, the teachings of men should never be the focus point of believers. This concept was demonstrated by the church in Philadelphia as mention in the Book of Revelation.
More reading for you: 10 Basic Christian Beliefs 
Resource – Scripture quotations are from The Holy Bible, King James Version