Christian unity is easy to talk about in the abstract, but much harder to live out in the ordinary circumstances of life. We can agree that the church should be unified while still finding it difficult to spend time with people who are different from us, bear the burdens of people whose struggles we do not understand, or sacrifice our own preferences for the good of someone else.
The cost of unity in the church is therefore worth considering carefully. Unity is not simply an ideal that Christians are encouraged to pursue, nor is it something we manufacture through enough agreement or organizational effort. Scripture presents unity as something God has already established through the Gospel, while also calling believers to actively preserve, mature, and express that unity in the way we live together.
In this lesson, which is a continuation of a lesson on unity in the church given in our singles ministry, the costs per-individual of being united in the church are counted.
Unity Is Something We Keep
In John 17, Jesus prays shortly before His arrest and crucifixion. His prayer is not limited to the disciples who are physically with Him. He looks ahead to everyone who will believe through their message:
“My prayer is not for them alone. I pray also for those who will believe in me through their message, that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me.”
— John 17:20–21 (NIV)
Jesus goes on to connect the unity of His followers with His own relationship with the Father. This makes unity in the church much more significant than simply getting along with other Christians. Jesus desires His people to reflect something of the relationship that exists between the Father and the Son, and He connects that unity directly with the witness of the church to the world.
Paul makes a similar point in Ephesians 4:
“Make every effort to keep the unity of the Spirit through the bond of peace.”
— Ephesians 4:3 (NIV)
The wording is important: Paul tells the church to keep the unity of the Spirit rather than create it.
The Gospel has already created a people who belong to one another. Paul emphasizes this with a series of “ones”: one body, one Spirit, one hope, one Lord, one faith, one baptism, and one God and Father of all. Christian unity is therefore grounded in something outside ourselves. It is grounded in the truth of who God is and what He has done through Christ.
That also means unity has boundaries. If the Gospel is one, then Christians cannot redefine the Gospel according to whatever happens to be convenient or culturally acceptable. Unity does not mean that every belief is equally valid, nor does it mean that Christians must agree about every question. Rather, it means that we are brought together around the truth of the Gospel.
Unity is to be Matured
Although unity is something God creates, living in that unity requires maturity.
Ephesians 4 continues by describing the gifts Christ gives to His church, including apostles, prophets, evangelists, pastors, and teachers. Their purpose is to equip believers for works of service so that the body of Christ may be built up and ultimately reach maturity in the faith and knowledge of Christ.
This gives us a different picture of spiritual growth. Maturity is more than simply knowing more information about Christianity, but is also learning to live out what we believe in relationship with other people. In this way, the Gospel transcends being viewed as a theory that exists in a vacuum into something visible in the way Christians treat one another.
That is particularly important because relationships are rarely simple. People misunderstand each other, disappoint each other, carry different experiences, and struggle with different weaknesses. Living in unity means learning how to follow Christ in the middle of those complications rather than waiting for relationships to become easy.
Jesus Himself provides the pattern. In John 17, He describes His relationship with the Father as one in which He does the Father’s will. His unity with the Father was not merely a statement of agreement, but was demonstrated through obedience, culminating in His willingness to sacrifice Himself on the cross.
If our unity is meant to reflect His unity with the Father, then Christian unity will also involve sacrifice.
Unity Costs Time
One of the simplest costs of unity is time.
Fellowship requires more than being in the same room. It requires knowing people, listening to them, checking on them, sharing life with them, and becoming aware of what they are carrying.
That becomes particularly important when someone is struggling. People do not always announce their burdens publicly, and sometimes they do not even recognize them clearly themselves. Meaningful fellowship creates opportunities for those burdens to become visible.
Paul writes to the Galatians:
“Carry each other’s burdens, and in this way you will fulfill the law of Christ.”
— Galatians 6:2 (NIV)
Carrying someone else’s burden requires knowing that the burden exists. This requires interaction, and interaction requires time.
It is natural to spend time with people who are already similar to us. We share interests, personalities, backgrounds, and experiences, so those relationships often develop without much effort. Yet the body of Christ includes people who are different from us, and those relationships can require greater intentionality.
Unity becomes particularly visible when believers choose to know and serve people they would not naturally choose as friends.
Unity Requires Sacrifice
Following Christ has always involved counting the costs.
Jesus did not merely receive God’s grace and continue living as though nothing had changed. His life was characterized by obedience and sacrifice. This same pattern applies to those who follow Him.
Dietrich Bonhoeffer in The Cost of Discipleship famously distinguished between “cheap grace” and “costly grace.” Cheap grace treats forgiveness as permission to remain unchanged, and costly grace recognizes that God’s grace brings us into a relationship with Him, and relationships require a response.
The same principle applies to Christian community.
Unity may require giving up time that could have been spent elsewhere. It may require listening when we would rather speak, forgiving when we would rather withdraw, confronting a difficult issue rather than avoiding it, or serving when nobody is likely to notice.
None of this earns God’s grace. Rather, it is a response to the grace we have already received.
Our Gifts Are Given to Serve Others
God has also given each believer gifts that are intended to strengthen the body.
Peter writes:
“Each of you should use whatever gift you have received to serve others, as faithful stewards of God’s grace in its various forms.”
— 1 Peter 4:10 (NIV)
A gift is not merely a personal ability to enjoy. It is something entrusted to us for the benefit of others.
This can look different from person to person. Teaching, listening, encouragement, discernment, music, hospitality, generosity, leadership, and many other forms of service can strengthen the church. Some gifts are obvious, while others are much less visible, but every part of the body has a role.
Having a gift does not eliminate the need for sacrifice. Even when something comes naturally, developing that gift and using it faithfully requires time and intentionality.
The body of Christ is healthiest when its members are actively contributing rather than remaining passive. Just as a physical body suffers when one of its parts becomes inactive, the church suffers when believers refuse to use what God has given them for the good of others.
If We Are Passive, We Become Vulnerable
Intentionality is therefore essential.
Relationships rarely remain healthy through neglect. If we are passive about our relationships with other believers, distance and misunderstanding can grow without much effort.
This is why Christian community requires initiative. We have to check on people, we have to ask questions, we have to notice when someone is struggling. We have to make time for people who may not naturally be part of our social circles.
Paul’s command to carry one another’s burdens assumes that we are close enough to know what those burdens are.
There is also a spiritual dimension to this. Jesus never promised that life together would be free from trouble. Instead, Scripture repeatedly prepares us for difficulty and teaches us how to respond to it.
The answer is not to withdraw from one another whenever relationships become difficult. The Gospel gives us the strength to remain present, because Christ Himself bore our burdens when we were far from Him.
Our ability to bear one another’s burdens ultimately comes from the grace that Christ has already shown us.
Unity Requires Maturity in God’s Word
Finally, Christian unity requires growing in our understanding of God’s Word.
Hebrews 5 describes maturity in terms of developing the ability to distinguish good from evil. That kind of discernment does not happen automatically, but comes through practice and through sustained engagement with God’s truth.
Romans 12 similarly calls believers not to conform to the pattern of the world, but to be transformed so that they can discern God’s will.
Spiritual maturity therefore requires more than familiarity with the basic ideas of Christianity. We must continue to study Scripture, wrestle with difficult questions, and allow God’s Word to shape the way we understand the world and respond to it.
The Bible is not meant to remain a theoretical document disconnected from ordinary life. We understand its teaching more deeply as we work it out in relationships, decisions, difficulties, sacrifices, and opportunities to serve.
The difficult situations of life often become the places where biblical truth moves from something we know to something we actually understand.
A Picture of Life Together
Acts 2 gives us one of Scripture’s clearest pictures of what this kind of community can look like.
The early believers devoted themselves to the apostles’ teaching, fellowship, breaking of bread, and prayer. They shared what they had, cared for those who were in need, met together regularly, ate together in their homes, and lived with glad and sincere hearts.
Importantly, their unity was not theoretical: It affected their calendars, possessions, homes, relationships, priorities, and worship.
“…and the Lord added to their number daily those who were being saved.”
— Acts 2:47b (NIV)
The church’s life together became part of its witness to the world.
This brings us back to Jesus’ prayer in John 17. Jesus prayed that His followers would be one so that the world would know that the Father had sent Him. Going beyond something that benefits Christians, unity is actually art of how the Gospel is displayed to those outside of the church.
We have been given a life together, and that life is worth investing in.
The cost is real. Unity requires time, sacrifice, service, intentionality, humility, and maturity. Yet none of these costs compare with the grace that made our unity possible in the first place.
Christ did not merely call us to believe the Gospel individually. He brought us into a body, gave us to one another, and called us to build one another up as we grow toward maturity in Him.
Do our lives demonstrate that we believe unity is worth the cost?