📖 Systematic Theology — Unit 9: Denominations, Authority, and the Gospel

Text: Ephesians 4:1-6 (NKJV)

Day 1 — Unity, Not Uniformity

Our text calls for unity, but we must be careful not to mistake unity for uniformity. Uniformity is an external sameness where everyone looks, speaks, and acts in identical fashion. Unity, however, is a spiritual reality — a "bond of peace" that exists in the heart despite outward differences.

Today, we look at a landscape filled with thousands of denominations. It is estimated that there are as many as 500 different Baptist denominations alone. We in this church are non-denominational, but that does not mean we are "belief-less." We have deep, grounded convictions. We recognize that while we may sit on different branches, we are still part of the same massive family tree, with many brothers and sisters in Christ.

The Jerusalem Genesis: To understand the current state of the church, we must return to its birth. The first church in the New Testament was not found in Rome, Constantinople, Geneva, Wittenberg, or anywhere else we might name today. It was born in Jerusalem.

In that first assembly, there were no buildings. There were no denominations. There were no signs out front telling you what kind of church it was. There were no systems, no seminaries, and no centuries of developed, formalized theology. There were simply people — people who had seen the risen Christ, people who had been filled with the Holy Spirit, and people who were devoted to the apostles' teaching, to fellowship, to the breaking of bread, and to prayer. It was simple. It was powerful. It was alive.

And yet — even there — there were differences. We sometimes imagine the early church as if everything was perfectly unified in every detail, but that is not what the New Testament shows us. Very early, questions began to arise: What do we do with Gentiles? Do they have to follow the law of Moses? What is essential, and what is not?

These were not small questions. In Acts 15, the leaders of the church gathered together for a council. They came together not to dominate one another, but to discern truth. They listened. They reasoned. They testified of what God had done. And they came to a conclusion grounded in the Gospel. From the very beginning, the church was unified in Christ — but it was never without tension.

Day 2 — The Great Divergence: Structure and Schism

As history moved forward, what began as a Spirit-filled movement slowly developed into a formal structure. Leadership became more defined, authority became more centralized, and doctrine became more formalized. For many centuries, the dominant expression of Christianity became what we now call the Roman Catholic Church.

But even that unity did not last. Differences grew in language, culture, theology, and authority. Eventually, in 1054, a "Great Schism" took place between the church in Rome (the West) and the church in Constantinople (the East). The Western church continued as the Roman Catholic Church, while the Eastern church became the Eastern Orthodox Church — still present today in Greece, Russia, and throughout Eastern Europe.

Then came the great turning points of history: the printing press, the Renaissance, and the recovery of the Greek New Testament. Suddenly, people began to read the Bible for themselves. Before this, the Bible was often chained to the pulpit to keep ordinary people from reading and potentially misinterpreting it. But when the chains were broken, there was a spiritual explosion. Movements of reform rose across Europe. Men began to challenge traditions — not because they wanted something new, but because they wanted to return to something original. They wanted to come back to Scripture.

From that came Protestantism, and from Protestantism came denominations. And that process has never stopped. Now, listen carefully: Not all differences are dangerous. Not all denominations are wrong. But not all teachings are harmless. Alongside legitimate expressions of Christianity, there have been movements that have gone so far that they have distorted the Gospel itself.

Groups like the Mormons and Jehovah's Witnesses do not simply differ — they redefine. They redefine Christ. They redefine salvation. They redefine the nature of God. And when the Gospel is changed, it is no longer the Gospel. The apostle Paul did not treat this lightly. He said in Galatians 1:9: "If anyone preaches any other gospel to you than what you have received, let him be accursed." The Gospel is not ours to improve or reshape.

Day 3 — The Catholic Church: Authority and the Foundation

We begin with the Catholic Church — the largest and most historically influential branch of Christianity.

The Pope and the Rock: At the center of Catholic teaching is a claim built upon the words of Jesus at Caesarea Philippi in Matthew 16:13-18. Jesus asks His disciples, "Who do men say that I, the Son of Man, am?" They give various answers. Then He asks, "But who do you say that I am?" Peter answers: "You are the Christ, the Son of the living God." Jesus responds: "And I also say to you that you are Peter, and on this rock I will build My church..."

Catholic theology says: Peter is the rock. Peter is the first pope. And authority flows from him. But look again at the central issue in the passage: "Who do you say that I am?" Peter's answer — the truth of who Jesus is — is the "Rock." That revelation is the foundation of the church. Jesus is not building His church on a man; He is building His church on the truth of His own deity. Scripture confirms this: "For no other foundation can anyone lay than that which is laid, which is Jesus Christ" (1 Corinthians 3:11). The church is not anchored in Peter; it is anchored in Christ, the chief cornerstone (Ephesians 2:20).

The Priesthood and Mediation: Catholicism establishes a priesthood — a system where grace is mediated through an ordained class. While there were priests in the Old Testament, the New Testament says something radically different: "You... are a holy priesthood" (1 Peter 2:5). Every believer has direct access to God. Furthermore, 1 Timothy 2:5 says: "There is one God and one Mediator between God and men, the Man Christ Jesus." There are not many mediators; there is one. This means you can take your prayers and confessions directly to the throne of grace. You don't need a priest because you are a priest.

The Treasury of Merit: There is the Catholic idea of "accumulated merit" from Jesus, Mary, and the saints. However, in the New Testament, every Christian was called a "saint." We are saints not because we are good, but because Jesus was good for us. Second, only Jesus was perfect. Everyone else, including Mary, was a sinner: "For all have sinned and fall short of the glory of God" (Romans 3:23). There is none that is righteous, no not one.

The Sacraments and Tradition: The Catholic Church teaches that grace flows through the sacraments. But Scripture teaches: "For by grace you have been saved through faith... not of works" (Ephesians 2:8-9). Grace is not administered through ritual; it is received through faith. Finally, Catholic teaching places tradition alongside Scripture. But the Bible says it is sufficient on its own: "All Scripture is given by inspiration of God... that the man of God may be complete" (2 Timothy 3:16-17).

Day 4 — Protestantism: Calvinism and the Reformed Tradition

Now we come to John Calvin and the Reformed tradition. He was a brilliant mind and a systematic thinker. He had points and sub-points and sub-sub-points. He wrote the Institutes of the Christian Religion, shaping theology for generations. His teaching is summarized in the acronym TULIP:

Total Depravity: Man is so affected by sin he cannot choose God on his own.

Unconditional Election: God chooses whom He will save based on His mercy.

Limited Atonement: Christ died specifically for the elect.

Irresistible Grace: When God calls, the soul will eventually respond.

Perseverance of the Saints: True believers will never fall away.

Reformed Balance and the Wider Protestant Family

The Danger of Balance and Predestination: There is truth here, but the danger is in what is emphasized beyond balance. Romans 8:29-30 and Ephesians 1:4-5 speak clearly of predestination. But some take this further and say God has predetermined some to heaven and some to hell. Scripture never says God is willing for people to perish; in fact, 2 Peter 3:9 says: "The Lord is not willing that any should perish..." God's sovereignty and God's heart are not in conflict.

The Preservation of Urgency: There is a story of a Presbyterian who fell down the stairs. Bruised but alive, he picked himself up, dusted off his clothes, and said: "Well... thank God that's over with." It's a funny story, but it reveals a deeper issue. When everything is viewed as strictly predetermined, the sense of urgency often fades. This was seen in the history of missions. William Carey, a Baptist who is considered the father of modern missions, wanted to go to Asia. An older pastor stood up and said, "Sit down, young man; if God wants to save the heathen, he can do so without your help or mine." Carey refused that idea. Because he refused it, modern missions was born.

The Paradox of Growth: Nearly every modern spiritual awakening began with the Presbyterians. It was as if the Holy Spirit chose the most "closed" and restrictive group to move with His power. Hundreds of thousands were converted in these Awakenings. But interestingly, the Presbyterians did not experience the greatest growth. Growth exploded among Methodists and Baptists. The Methodists believed in our free will to accept God's offer of salvation. The Baptists, while often Calvinistic, were very practical (after all, these were new warm bodies for the pews and potential tithers). They didn't let a little theology get in the way of evangelism, eventually leading Baptists to become a "hybrid" of Calvinist and Arminian views.

Day 5 — The Arminian Pillar: Grace, Human Response, and Continuing Faith

Alongside the Reformed tradition stands Arminianism, associated historically with Jacob Arminius and later strongly represented by John Wesley and the Methodist movement. It emphasizes both the necessity of divine grace and the genuine responsibility of the individual to respond to God in faith.

Grace and Human Response: Classical Arminians agree that fallen humanity cannot save itself. They commonly speak of God’s prevenient grace as grace that enables a real response to the Gospel. The offer of salvation may therefore be accepted or resisted; faith is not produced by an irresistible decree. Calvinists answer that saving grace effectively brings the elect to faith. Both traditions intend to take seriously biblical teaching about grace, faith, human inability, and God’s sovereignty, but they arrange those truths differently.

Perseverance, Security, and Apostasy: Christians also disagree about how to understand a person who once made a credible profession of faith, was received by the church as a brother or sister, but later abandons faith in Christ. Reformed theology teaches the Perseverance of the Saints: those truly regenerated by God will be preserved in faith to the end. From this perspective, final apostasy reveals that the earlier profession, however convincing it appeared, did not arise from genuine regeneration. Classical Arminian and Wesleyan theology allows a different explanation: the earlier faith may have been genuine, but the believer later abandoned that faith and fell from grace. Thus both traditions take apostasy seriously, but they differ over what the apostasy reveals about the person's earlier spiritual condition and over how divine sovereignty, preserving grace, human response, and continuing faith relate to one another. Other evangelical Christians combine an Arminian understanding of human response with eternal security. CTS does not require students to adopt one denominational system on this question. It does insist that salvation is entirely dependent on the grace of God in Christ, is received through faith, and that the New Testament repeatedly calls believers to continue trusting and following Christ.

The Charismatic and Pentecostal Expansion: Under the broader Arminian umbrella, we also find the groups that practice the Charismatic gifts. This includes Pentecostals, the Assemblies of God, and many other Charismatic groups. These groups elevate certain spiritual gifts, such as speaking in tongues and healing. Whether we agree with their specific practices or not, we know they are the fastest-growing groups in Christianity around the world. The Holy Spirit is certainly using the Charismatics, and we should be very careful about criticizing anyone whom the Holy Spirit is using.

Final Lessons

1. Scripture Stands Above Tradition: This includes our own traditions. If there is a conflict, we must return to the New Testament model.

2. The Command of Missions: People without Christ are lost. Jesus said in Matthew 28:19-20: "Go therefore and make disciples of all the nations, baptizing them... and lo, I am with you always, even to the end of the age."

3. Essential Doctrine Must Be Protected: The Gospel is not ours to improve or reshape. When the Gospel is changed, it is no longer the Gospel.

Final Summary

The doctrine of denominations and authority teaches us that while the church was born in unity, differences developed over time. Not all differences are dangerous, but when the Gospel itself is redefined, it becomes another gospel altogether. The Catholic Church emphasizes tradition and papal authority. The Reformed tradition (Calvinism) emphasizes God's sovereignty and predestination. The Arminian tradition emphasizes God-enabled human response and resistible grace; many classical and Wesleyan Arminians also affirm the possibility of a genuine believer finally falling away from faith. The Charismatic and Pentecostal movements emphasize spiritual gifts and have become the fastest-growing Christian groups worldwide. Through all these traditions, Scripture must remain the final authority. The Gospel must be protected. And the mission to make disciples must never be abandoned.