Was Christianity Ever Unified? How Christian Beliefs Evolved Across History

I want to take you on a thought process that I am still actively sitting with. I do not know that I know exactly where it lands, but I do know it keeps showing up in my reading and in the way I see the Bible functioning as a whole. So I am going to lay it out as clearly as I can. It might feel like I am processing out loud in written form. That is because I am.

Here is the premise. At every point in the history of belief, and at every stage in the formation of what we call the Bible, we are dealing with a culture and a language and a people living at a specific time in a specific place, experiencing God in a specific way. That experience, and those pressures, shape how they talk, how they write, how they compile, how they organize, how they edit, and how they frame this library of texts. And then, after those texts exist, God continues to speak through them into real human beings who are also living in specific places at specific times, which means belief keeps getting wrestled with, clarified, challenged, refined, and sometimes corrected.

And because of that, I keep coming back to a question that a lot of faith communities do not like to ask. Was Christianity ever unified? Not in the way many people mean it. Not as a single, static, fixed, uniform belief system that never changed and never adapted and never moved. That version of the story is comforting, but it is not honest to the history.

Now, before somebody hears that and jumps straight to, Joe is turning into a relativist, let me say this as plainly as I can. My theological anchor is Jesus. Not a system. Not a tribe. Not a fear based need to be right. Jesus. I believe the primacy of the Bible, for anyone who wants to live by it, is that it points us to the person of Jesus and invites us to align our lives to his way. I am not saying truth does not exist. I am not saying anything goes. I am saying the story is more complicated than we often pretend it is, and the evidence for that complexity is everywhere once you slow down and look.

So I am going to walk through a handful of moments across history that make this hard to ignore. I am not trying to dump a textbook on you. I am trying to show you a pattern. Belief has always moved. It has always developed. It has always been shaped by real circumstances. And if that is true, it should change the way we talk about faith today.

Let’s start where a lot of people have not spent much time. The period after the exile.

Most people know the basic outline. Israel goes into exile. Babylon falls to Persia. Cyrus issues a decree. Some of the exiles return. Jerusalem gets rebuilt. Ezra and Nehemiah show up. The temple gets restored. The walls go back up. End of story.

But that is not the whole story. That is the story as told from one perspective. And that matters.

When the Persians came to power, they did not operate like the Assyrians and Babylonians had. The Assyrians and Babylonians often conquered by removing people, relocating populations, importing new communities, and reshaping the cultural fabric of the land. Persia had different political instincts. They were more interested in stability and local governance than total cultural replacement. So yes, exiles returned, but not everybody returned. And the land was not empty. People had remained. Communities had formed. Worship had continued.

Now add another layer. Long before Babylon, Assyria had conquered the northern kingdom, Israel. When Assyria took the north, they renamed that region Samaria. People remained there too, and new populations mixed in over time. There were still Yahweh worshippers in the north, but their life was not centered in Jerusalem. Jerusalem was damaged, diminished, and at points functionally irrelevant for large stretches of time. That vacuum does not stay empty. Something always fills it.

So in the north, worship and identity consolidated around Samaria and Mount Gerizim. In the south, the memory and hope of Jerusalem remained, even if Jerusalem was not yet restored to power. By the time exiles began returning under Persian rule, there were already competing centers of Yahweh worship, competing claims of legitimacy, and competing visions for what the future should look like.

That is where the story of Ezra and Nehemiah gets more interesting.

There were phases of return and rebuilding. You have the early movement associated with Zerubbabel and Joshua the high priest, which is focused on temple rebuilding. You have Ezra coming later with a major emphasis on Torah and reform. You have Nehemiah coming later still with the rebuilding of the walls and the reinforcing of boundaries.

And that word boundaries matters. Because what Ezra and Nehemiah were doing was not simply rebuilding infrastructure. They were rebuilding identity. They were drawing lines. They were deciding who belonged and who did not. They were trying to shape a people who would not repeat the mistakes of the past. In their mind, syncretism and divided worship led to exile. So the way forward, the way to survive, the way to be faithful, was exclusive Yahweh worship and centralized worship in Jerusalem.

But the people in Samaria did not agree. They worshipped Yahweh too. They had Torah too, though in their own form. They did not accept the prophets and writings in the same way the Jerusalem centered group did. That is not random. That is strategic. If you reject the prophetic and Davidic traditions, you can reject Jerusalem’s claim to be the one true center. If you reject the Davidic promise, you remove one of the theological engines driving Jerusalem restoration.

So you have a real conflict. You have a competition of visions. You have one group saying, we are reforming around Torah, Jerusalem, and exclusive Yahweh worship. You have another group saying, we are already worshipping Yahweh. We already have a center. We have no interest in surrendering it just because you returned from exile and want to take control again.

Now here is the key point. The texts we have, Ezra and Nehemiah and the prophets tied to that era, are told from the perspective of the Jerusalem centered reform movement. They do not narrate the full complexity. They narrate what supports their theological aim. That is not necessarily malicious. That is how theological history works. It is written with a purpose.

But when you see the wider context, you realize something. Even within Yahweh worship, even within what becomes Judaism, there was never a single unified belief system. There were debates. There were competing claims. There were different scriptures treated as authoritative. There were different temples. There were different centers. There were different understandings of how God’s presence and favor functioned.

And this is also where you begin to see a movement from henotheism toward something closer to full monotheism. Henotheism is basically this idea that you worship one god as your primary deity, but you acknowledge the existence of other deities. A lot of ancient religion functioned that way. Even within Israel’s history you can see traces of that worldview. The reform movement associated with Ezra and Nehemiah pushes hard toward exclusivity. Yahweh alone. No rivals. No mixture. No blending. That becomes a defining boundary marker.

So already, right there, belief is evolving. Not because people are bored. Not because they want novelty. Because history happened. Empires rose and fell. The land got reshaped. Communities split and rebuilt. Leadership changed. And the people had to interpret their experience with God inside all of that.

Then you move forward to the first century, and it makes sense that the center of gravity is Jerusalem again. The temple is there. Rome is in power. People are longing for liberation and kingdom. The expectation of Davidic fulfillment is alive. The whole story has been reoriented around Jerusalem, and now the question is what does God do next?

Jesus steps into that moment and he does something that feels very familiar if you have been paying attention. He reframes. He reworks. He intensifies. He exposes distortions. He takes what people assumed was fixed and he either deepens it, redirects it, or challenges it.

You hear it in the Sermon on the Mount. You have heard it said, but I say to you. That is not Jesus doing a cute rhetorical trick. That is Jesus claiming authority to interpret Torah and to reveal what people had missed. Sometimes he affirms the command and takes it deeper. Sometimes he confronts the way the command has been used. Sometimes he exposes the heart behind it. But the pattern is consistent. Jesus is moving belief forward.

He also reframes the temple itself. He speaks of its destruction. He speaks of rebuilding in ways people do not understand until later. The Gospel writers even tell you that. They will say, we did not understand what he meant when he said this. That should tell you something. Jesus was not simply reinforcing what everybody already believed. He was disrupting it.

And then Paul takes the disruption even further.

If Ezra and Nehemiah were about boundary reinforcement, Paul looks like boundary demolition. Not because Paul hates holiness. Because Paul believes God has done something in Jesus that changes the structure of belonging itself.

The Gentile question is not a minor theological footnote. It is an earthquake. Who is included in the people of God, and on what basis? Do Gentiles have to become Torah observant? Do they have to be circumcised? Do they have to take on Jewish identity markers in order to belong?

Acts 10 to 15 shows you these arguments playing out. Peter has a vision. Food comes down. Unclean and clean categories get challenged. And the voice says, do not call unclean what I have called clean.

That is not just about food. That is about people. That is about identity. That is about belonging.

If you only know a version of Christianity where everything was settled from day one, this will mess with you. Because the early Jesus movement was actively debating what faithfulness looked like in light of what they believed God had done in Jesus. They were not just repeating a static system. They were wrestling. They were adapting. They were interpreting scripture in new ways because they believed God was doing a new thing.

Now zoom out beyond the New Testament, and the same pattern keeps going.

As Christianity spreads into the wider Greco Roman world, it runs into philosophical categories and assumptions that Judaism did not have to address in the same way. So now the big debates are not only about Torah and temple and belonging. Now the debates are about who Jesus is. What is his relationship to God? What do we mean when we call him Lord? How do we talk about the Spirit? What is the relationship between Father, Son, and Spirit?

These conversations did not happen in a vacuum. They were shaped by the intellectual environment of the time. Greek philosophical frameworks influenced the language Christians used to articulate what they believed. That does not mean Greek philosophy replaced scripture. It means scripture was being interpreted in the real world, using the tools and categories available, in order to communicate what Christians believed was true.

And those debates were not clean. They were not simple. They were messy, political, relational, power laden, and complex. Councils happened because people disagreed. Creeds formed because people were trying to draw lines. Orthodoxy did not arrive as an obvious package everybody instantly recognized. It formed through conflict and conversation.

Then you get to the East and West split.

At a very broad level, the Latin speaking west develops along one line, and the Greek speaking east develops along another. Different languages. Different liturgies. Different cultural instincts. Different political pressures. Different structures of authority.

The west increasingly centralizes authority around the bishop of Rome, the papacy, with a strong claim to Petrine succession. The east emphasizes conciliar leadership, councils, shared authority, and continuity of practice. They do not accept a single universal leader in the same way the west does. Over time, those differences become fractures. The fractures become a schism.

Both sides argue their faithfulness. Both sides appeal to scripture. Both sides claim continuity. Both sides believe they are preserving the true shape of the church.

So again, unity in the simplistic sense was never the reality. There was always diversity, disagreement, and development.

Then the Reformation happens, and you get another major shift.

Luther is not operating in a timeless theological bubble. He is reacting to a real context. Indulgence sales. Abuses of power. Pastoral fear. Guilt. Anxiety. A system that, in his mind, had drifted away from the center.

So he pushes back. And he appeals to scripture. And what is fascinating is that Rome also appeals to scripture. The argument is not usually, who has scripture, and who does not. The argument is, whose interpretation is faithful.

Then even within the Reformation, you have divergence. Luther and Zwingli cannot agree on the Eucharist. Calvin develops his own system. Other movements arise. Anabaptists. Baptists. Methodists. Puritans. On and on it goes. And now we live in a world where thousands of denominations exist, and most of them can produce Bible verses to justify why they do what they do.

That should tell you something important. The idea that belief was once fixed, certain, and uniform, and then somehow got polluted later, does not match the historical record. Belief has always been in motion.

Now let me land this in the place that matters most to me.

The conclusion is not, nothing matters. The conclusion is not, truth is only relative to culture. The conclusion is not, the Bible has no authority. The conclusion is not, Jesus is just one option among many.

Here is my actual point.

We need to stop pretending that culture is the enemy of faith. Culture has always been part of how faith gets expressed, formed, and communicated. The question is not whether culture influences belief. It always has. The question is whether our belief is being aligned to the centrality of Jesus, or whether it is being driven by fear, power, and the need to control.

Because this is where I get blunt. If you claim to follow Jesus but your life does not resemble the fruit of the Spirit, you do not look like Jesus. Gentleness. Patience. Kindness. Goodness. Faithfulness. Self control. These are not optional extras. They are the evidence of what kind of spirit is shaping you.

So whenever I am wrestling with theology, my grid is not, does my tribe agree with me? My grid is, does this align with the ethic of Jesus? Is this rooted in love? Does it move me toward loving God and loving my neighbor? Or is it rooted in fear? Is it producing contempt? Is it producing arrogance? Is it producing division for the sake of being right?

That is why I can say unity matters, but uniformity is not the goal. Paul talks about a body with many parts. Different gifts. Different expressions. Different roles. Unity does not mean sameness. It means love centered cohesion.

So if you are someone who has been told that the goal is a fixed system you must never question, I want to gently challenge that. The people who gave us the Bible questioned. They debated. They wrestled. They interpreted. They lived in real history. Jesus reframed what people thought was settled. The early church did not have everything instantly locked down. Belief developed. It always has.

And here is the wild part. I actually think that can be good news.

Because if you are spiritually curious, skeptical, unsure, tired of manipulation, tired of fear based religion, tired of feeling like you have to pretend certainty you do not have, this opens a door. It means you can be honest. You can wrestle. You can grow. You can learn. You can change your mind. You can ask better questions. You can be a person of faith without being trapped in the illusion that mature faith means never evolving.

Ask me what I believe right now, and I will tell you. But ask me again in a month, and I might have learned something that expands it or reframes it. That is not a failure. That is what it means to be a human being learning to trust God in the real world.

So my invitation is simple. Keep the centrality of Jesus. Hold your beliefs with humility. Stay rooted in love. Be willing to listen. Be willing to learn. Be willing to admit complexity. And do not be shocked when you discover that the story of belief has always been more human, more messy, and more historically grounded than the tidy versions many of us were handed.

If God has always been speaking through texts that were formed in real history, to real people, in real cultures, then it makes sense that God continues to speak through those texts into our real lives too. The challenge is not to freeze belief in place. The challenge is to keep aligning ourselves to the best way to be human that Jesus reveals and empowers, and to let that shape how we live, how we love, and how we carry faith forward.