What Is Unity in the Bible, Actually?

The origin story of the church is both profound and simple. Jesus died in our place and was raised from the dead (1 Cor 15:1–4). He appeared to his disciples, commissioned them to make more disciples (Matt 28:18–20), and then empowered them by his Spirit to do so (Acts 1:8).

That group of disciples was small enough to fit into a single room when they gathered together in Acts 1:12–26. Under the leadership of the apostles, they prayed and carefully discerned their next steps.

Acts 2 describes that monumental day during the Feast of Pentecost. While worshipping together in the upper room of a home in Jerusalem, the Spirit descended upon the disciples in power. Peter preached his famous sermon and thousands of people found Jesus and flooded into this new movement.

The church outgrew the upper room, but that growth came with the pain of division and fragmentation. And the church has continued both to grow and fragment ever since.

Jesus clearly wants his church to grow, or he wouldn’t have commanded us to “make disciples of the nations” (Matt 28:19). And Jesus also clearly wants church unity, or he wouldn’t have prayed for it so passionately (John 17:11, 20–23). In fact, on the edge of death, unity occupied the heart and mind of Jesus.

Jesus’s prayer for our unity

Jesus prayed for his disciples, and he prayed “for those who believe in me through their word” (John 17:20). Anyone who has heard the apostles’ teaching and believed in Jesus is included in this prayer. It involves every single person who has put her faith in Jesus in the last two thousand years, including you and me.

Just before the cross, Jesus prayed for us, and the first thing on his heart in that moment was our unity.

May they all be one, as you, Father, are in me and I am in you. May they also be in us, so that the world may believe you sent me. I have given them the glory you have given me, so that they may be one as we are one. I am in them and you are in me, so that they may be made completely one, that the world may know you have sent me and have loved them as you have loved me. (John 17:21–23)

We need to take unity seriously because Jesus took it seriously. He didn’t treat it as something optional. Unity, according to Jesus, isn’t just for the health of the church (though it certainly is). Jesus also notes that our unity is to be a witness to the broader world. Our capacity to be unified as the people of God is deeply missional.

Jesus wanted his people to demonstrate a unity that could somehow faintly mirror the Trinity: “So that they may be one as we are one” (John 17:22). So when Jesus was praying, he was thinking of a oneness so perfect that theologians have struggled to define it, or even to describe it. And he was praying with full knowledge that his people would often struggle for anything resembling such unity.

The church’s need for unity

John was paying attention. It shouldn’t surprise us. John was close to the heart of Jesus, both literally and figuratively. On the night before the crucifixion, John “was reclining close beside Jesus” (John 13:23). This physical closeness expressed the love Jesus had for John. He was called “the one Jesus loved” (John 13:23; 19:26; 20:2; 21:7, 20).

John certainly had told and preached the story of overhearing Jesus pray many times before. But John didn’t actually write down the biographical account of Jesus’s life until fifty or more years later. By that time, the church had experienced profound growth, deep suffering, and tragic divisions.

John’s Gospel was one of the last books of the New Testament to be written. And this early history wasn’t a pristine era of unified innocence. Divisions started almost immediately. From the Greek-speaking widows getting overlooked in Acts 6, to the Corinthians picking teams: “‘I belong to Paul,’ or ‘I belong to Apollos,’ or ‘I belong to Cephas,’ or ‘I belong to Christ’” (1 Cor 1:12).

So in John 17, Jesus wasn’t praying with rose-colored glasses, and John wasn’t writing from a place of youthful idealism. Jesus knew what would happen, and John knew what had happened. And yet unity was so critically important that Jesus pleaded with the Father for it, and John made sure we all would know about that prayer.

In that sense, when John drew out the emphasis on unity in Jesus’s prayer, he was not only giving a historical account of what had happened. He was also giving a prophetic account of something he believed Jesus longed for the church to live into. Likewise, when Luke described the unity of the early believers in Acts, he was both describing a quality he observed and a hopeful ideal that they might continue to embody. Both John and Luke wanted us to read their words and reflect on the unity of the early church, not to make us long for “the good ol’ days” but to help us lean into the unity which the gospel makes possible.

The Bible’s concept of unity

The Bible’s view of unity is not sameness or uniformity. We see this clearly in John’s vision of the throngs of worshippers before the throne of the Lamb in Revelation 7. Those, John sees, are both united and yet still different from one another, that is, from every tribe and tongue (Rev 7:9; cf. 5:9). The gathered assembly is both fully unified in worship of Jesus and yet made up of incredibly diverse peoples.

Unity requires differences that are transcended in something beyond those differences. Jesus roots our unity in a transfer of glory (John 17:22) and his own indwelling within us (John 17:23). In other words, unity is rooted in the life that Christians share in Christ. Christians are united because we have been reconciled to God through Jesus and adopted into one family by the Spirit.

Paul makes this source of unity clear in Ephesians 4, grounding unity in the realities we share in Christ:

There is one body and one Spirit—just as you were called to one hope at your calling—one Lord, one faith, one baptism, one God and Father of all, who is above all and through all and in all. (Eph 4:4–6)

Christians are already united in Christ, yet we are commanded to be “making every effort to keep the unity of the Spirit” (Eph 4:3).

This effort assumes difficulty. It presupposes struggle. Unity does not happen automatically. Christians are sinners saved by grace who still disagree, misunderstand, and hurt one another. Unity takes work. In other words, we don’t achieve unity. Instead, we receive unity in the gospel, and then we live into it.

We don’t achieve unity. Instead, we receive unity in the gospel, and then we live into it.

Unity does not require the absence of disagreement but a bond deeper than the disagreement. Believers remain brothers and sisters even when closeness varies. And as church history has unfolded, those relationships have taken quite a few twists and turns.

Study topics like the church’s unity with Logos’s Factbook.
Try Logos for free!

Christianity’s growth—and fragmentation

As we have seen, the church never experienced a season of pure unity. Divisions and disagreements emerged within the lifetimes of the apostles and continue to the present day.

For example, in the persecutions that broke out before the acceptance of Christianity by Rome, bitter disagreements existed between Christians as to whether believers should evade persecution or meet it head-on. In the fourth century, churches divided over the teachings of a man named Arius, who argued that Jesus was a created being and not fully God. In response, the church agreed on a summary of apostolic teaching formalized in the Nicene Creed.

As the Roman world began to splinter, so did the church. In Eastern Christianity, centered in Constantinople (now Istanbul), the Assyrian, Coptic, Armenian, and Syrian churches splintered off in the fifth century. Not long after, the first fissure between Eastern and Western Christianity appeared, eventually culminating in the Great Schism of 1054.

Western Christianity’s divides came later but were no less significant. In the fourteenth century, rival popes jockeyed for power. The sixteenth century birthed the dawn of the Protestant Reformation. These “Protestants,” such as Martin Luther, didn’t initially want to split from Rome. But they quickly had no choice.

Different Protestants in turn had different visions for church life. The splintering of the many denominations we see today was fully in motion.

Why so many denominations?

As Christianity has continued to grow and fragment, billions of people now claim to follow Jesus across nearly fifty thousand denominations.¹ Yet generally, their differences can be poured into four distinct “buckets.”

Of the four buckets, each of the following is sequentially less “weighty” than the last. Imagine the first bucket being filled to the brim with water, and the fourth, the practical bucket, being filled only a fraction of the way. This would make the first bucket much “heavier” than the last one. That said, some buckets are functionally filled with more weight than others at different points for different groups.

1. Theology

For instance, Protestants separated from Catholics over fundamental theological issues, such as salvation by grace through faith alone and the Bible as our sole infallible authority.

In terms of theological differences, we can define three levels of importance:

1. Essential beliefs are doctrines that all Bible-believing Christians share, regardless of denomination or context. A person or group who doesn’t believe in the Trinity, the authority of Scripture, or the deity of Christ is simply not Christian. We are one in Christ with all Christians who share these essential beliefs. We are not united with those who don’t.
2. Convictional beliefs often shape denominational distinctions. These second-level doctrines might be specific practices of baptism or beliefs about the role of sovereignty and free will in salvation. Christians are still one in Christ despite such differences, but we typically end up in different denominations because of them.
3. Preferential beliefs are important but often allow room for disagreement within denominational traditions and even within individual local churches. A typical example is eschatology, or another could be how loud the music is during worship.

2. Structure

These differences center around church polity. For example, I teach twice a year at Wycliffe Hall at the University of Oxford, an evangelical Anglican institution. Anglicans have bishops, while other groups might have presbyteries or congregational rule. Christians who disagree about how to structure the church have ended up organizing themselves into different types of denominations.

3. Culture

These can be more neutral differences—or more negative ones. For example, during the Jim Crow era, black members of the Assemblies of God (then overwhelmingly white) separated and formed their own denomination, the Church of God in Christ. Many denominations within the United States were formed over racial tensions of this sort. That said, many have become remarkably diverse today, with beautiful reconciliation, as we have seen between the Assemblies of God and the Church of God in Christ.

4. Practice

Style of worship and the importance of established rituals and traditions create some diversity. Christians who differ on very practical things tend to cluster together with others of a similar mindset.

Pursuing gospel partnership

We are one with all actual Christians, even if we might be out of relationship with them in certain ways. Yet as we identify these differences, we can begin to navigate them and move toward fruitful gospel partnership and unity.

My youngest daughter recently sat down with my wife Donna and me. She nervously told us she had something to tell us. (We held our breath.) She explained that she loved us and the Lord, and she was becoming Anglican. Donna and I looked at each other, exhaling with relief. We said, “If this is your long-awaited rebellion against your parents, we will gladly take it!” We agree on the essentials, and we thank God for what he is doing in Anglican churches that share the essentials, even if they differ with us on some convictions.

On the other hand, some parts of some denominations deny essential doctrines. Yet many of those denominations still have people within them who are genuine Christians. We live in a messy and broken world, and the church isn’t immune.

So, when we walk with others, we must do so “with all humility and gentleness, with patience, bearing with one another in love, making every effort to keep the unity of the Spirit through the bond of peace” (Eph 4:2–3). Humility means that we don’t need to win every argument. Gentleness is strength under the Spirit’s control. Patience means slowing down to love imperfect people. Bearing with one another means sometimes literally putting up with one another.

What we have in common is far greater than what separates us. We already have unity in Christ, and we’re called to lean into that unity. It requires effort and spiritual sweat, in hope that Jesus will finally and fully reunite his church from every place and people around his throne (Rev 5:9; 7:9).

Share your thoughts

How would you define unity according to the Bible? Join us in the Word by Word group to share your thoughts.

Resources for further reflection

Related content

• One, Holy, Catholic & Apostolic: The 4 Marks Explained
• What Romans Teaches Us about Church Unity
• Where Comfort Goes to Die: Christian Community Beyond Homogeneity
• Unity without Compromise: Councils & Creeds for Today’s Ecumenical Dialogue
• How Can Churches Across Town Partner Together?

1. This figure can mislead as to the extent of division, though, since it includes every national branch of a similar denomination, a large number of independent bodies, and denominational institutions that share the same core doctrine and tradition. For more on how denominations are defined and categorized, see Steven Wedgeworth, “Definitive Guide to Christian Denominations,” Word by Word, Logos (blog), October 27, 2023.