The Requirements for Unity (October 11, 2026)

A sermon by Jeremy Isaac on Ephesians 4:1-3
Hot Springs Reformed Church · Hot Springs, SD

Introduction: Unity Without a Definition

Unity is probably something you’ve heard about. At various times and in various places it’s a buzzword, both in Christian circles and elsewhere, and the emphasis on it is rightly placed. Psalm 133 is a good example (a psalm we may sing next week; we didn’t have it this week):

Behold, how good and how pleasant it is
For brothers to dwell together in unity! (Psalm 133:1)

Unity is important. In John 17, the great high priestly prayer, Jesus says, “I in them and You in Me, that they may be perfected in unity, so that the world may know that You sent Me” (John 17:23). So we are told that unity is good, and that it’s something we ought to seek.

But in my experience, not only is it hard to find examples of unity, it’s really hard to find anyone even willing to define what Christian unity looks like. People write articles about it, but when it comes time to land the plane, they obscure any concrete conclusions and leave us with empty platitudes. At best we might get something like the saying you’ve probably heard, almost certainly attributed to the wrong person: “In essentials, unity; in non-essentials, liberty; in all things, charity.”

That probably sounds familiar. The proper attribution, by the way, is a German Lutheran theologian of the early seventeenth century, Rupertus Meldenius. You all knew that, I’m sure. It was not Augustine, it wasn’t Lewis, and it wasn’t anyone in between. It was this Rupert guy.

Anyway, it sounds good, doesn’t it? “In essentials, unity; in non-essentials, liberty; in all things, charity.” But even that statement, when you really get down to the nitty-gritty, doesn’t tell us how to have unity, or even what unity really looks like. In fact, the statement may be more problematic than it first appears. It has long been the official motto of the EPC, the Evangelical Presbyterian Church. And while the EPC was formed in the early 1980s for the express purpose of pushing back against the liberalism of other Presbyterian denominations, it is with this motto leading the way the EPC itself has gone down the same well-trodden path as most who focus on unity. For whatever reason, as soon as a church puts the word unity in its name, or its denomination’s name, we can see exactly which direction it’s going.

If we didn’t know better, we’d think unity only goes in one direction: toward compromise and what we might call, to be charitable, minimalist theology, a belief in only the bare minimum required. Now obviously, when Jesus prayed for unity, or when Paul preached unity here in Ephesians, this is not what they had in mind. So we must find a different way.

My goal for the next few sermons is quite simple, though perhaps a bit ambitious in light of what we’ve just discussed. One, I simply want us to understand what unity truly is. And two, I want us to know practically how we should conduct ourselves in pursuit of that unity.

Having said that, you might expect me to give you a definition now. I’m not going to do that just yet. Instead, we’ll start by gathering some of the pieces, parts of the whole that hopefully we can grasp, and then come back around in a week or three and, hopefully, give you a succinct definition you can remember. For now, we’ll gather the pieces and start putting the picture together.

Then, once we finish discussing unity, we will put it to the test as we move on to discussing baptism. We’ll seek to maintain our unity, and even grow in it, while discussing what has historically been one of the most polarizing issues in the church. So the next couple of months should be exciting.

With that, let’s read our passage to orient ourselves, and then we’ll get into it. I’ll start in Ephesians 3:20 and read through chapter 4, verse 16.

Scripture Reading: Ephesians 3:20–4:16

Ephesians 3:20 Now to Him who is able to do far more abundantly beyond all that we ask or think, according to the power that works within us, 21 to Him be the glory in the church and in Christ Jesus to all generations forever and ever. Amen.

4:1 Therefore I, the prisoner of the Lord, implore you to walk in a manner worthy of the calling with which you have been called, 2 with all humility and gentleness, with patience, showing tolerance for one another in love, 3 being diligent to preserve the unity of the Spirit in the bond of peace. 4 There is one body and one Spirit, just as also you were called in one hope of your calling; 5 one Lord, one faith, one baptism, 6 one God and Father of all who is over all and through all and in all. 7 But to each one of us grace was given according to the measure of Christ’s gift. 8 Therefore it says,

“WHEN HE ASCENDED ON HIGH,

HE LED CAPTIVE A HOST OF CAPTIVES,

AND HE GAVE GIFTS TO MEN.”

9 (Now this expression, “He ascended,” what does it mean except that He also had descended into the lower parts of the earth? 10 He who descended is Himself also He who ascended far above all the heavens, so that He might fill all things.) 11 And He gave some as apostles, and some as prophets, and some as evangelists, and some as pastors and teachers, 12 for the equipping of the saints for the work of service, to the building up of the body of Christ; 13 until we all attain to the unity of the faith, and of the knowledge of the Son of God, to a mature man, to the measure of the stature which belongs to the fullness of Christ. 14 As a result, we are no longer to be children, tossed here and there by waves and carried about by every wind of doctrine, by the trickery of men, by craftiness in deceitful scheming; 15 but speaking the truth in love, we are to grow up in all aspects into Him who is the head, even Christ, 16 from whom the whole body, being fitted and held together by what every joint supplies, according to the proper working of each individual part, causes the growth of the body for the building up of itself in love.

This is the word of the Lord. Thanks be to God.

The Big Picture

I’m going to begin with a quick summary of this entire passage, so we see the overall lay of the land, and then we’ll dive a little deeper into the first couple of verses.

We started at Ephesians 3:20, which we talked about a couple of weeks ago: “Now to Him who is able to do far more abundantly beyond all that we ask or think.” Then in verse 1 of chapter 4 he says, “Therefore.” When we see that, we look back and ask what was taught previously that he is tying into. While we could say it’s really the whole first half of Ephesians, I think he’s also tying back very specifically to those last couple of verses. As we seek unity, it will require the power he promises in chapter 3, verse 20.

Paul says, “I… implore you to walk in a manner worthy of the calling.” Paul is pleading with the Ephesians. This is not something academic for him; it’s near and dear to his heart. It’s somewhat reminiscent of Jesus’ intense and fervent appeal to the Father in John 17, when He prays for unity.

Walking worthily

He goes on to say we are to walk in a manner worthy of the calling. To walk here refers to our overall manner of life. If you’re in the King James, the old English word is conversation; it’s the same idea. It refers to the whole manner of how you go about living in this world.

Colossians 1:10–11 explains what it means to walk in a worthy manner:

so that you will walk in a manner worthy of the Lord, to please Him in all respects, bearing fruit in every good work and increasing in the knowledge of God; strengthened with all power, according to His glorious might, for the attaining of all steadfastness and patience;

In a word, when he implores us to walk in a worthy manner, he is desiring our sanctification. That is really what this is. The call to walk worthily is a call to sanctification: a call to live your life more and more like Christ Jesus, our example, every day.

This theme of walking comes up throughout the rest of Ephesians as well. So I want to pause for a moment and point out that I believe “walk in a manner worthy” actually describes the rest of the book. All of chapters 4, 5, and 6 could be lumped under it, because it’s all about our sanctification, all about walking worthily:

It was first mentioned back in 2:10, where we were prepared to walk in good works.
Here we have walk in a worthy manner (4:1).
In 4:17, to walk with a renewed mind.
In 5:2, to walk in love.
In 5:8, to walk as children of light.
In 5:15, to walk in wisdom.

So for the rest of the book, Paul is instructing us in our walk, in our life. While the first part of the book was heavier on theology (how we were to understand things, what we were to believe), he now makes it very practical and instructs us how to walk in light of that.

And then, almost as if Paul had a sense of humor, he tells us that the first way we’re going to start working on our walk, on our sanctification, is in dealing with other Christians and striving for unity. We might say, “Paul, maybe give us an easier one to start with.” But that’s right where he jumps in. He narrows the focus from our sanctification broadly to this particular concern: preserving “the unity of the Spirit,” as we see in verse 3.

A preview of the passage

And this becomes the main theme for the next sixteen verses, everything we just read. Today, in verses 1–3, we’ll look at the requirements for unity. Let me give you a quick snapshot of what’s coming, because I think it will help us understand today’s passage as well.

The tools for unity. In the coming weeks we’ll look at what I’ve labeled the tools for unity: “with all humility and gentleness, with patience, showing tolerance for one another in love.”
The doctrines of unity. Later we’ll look at the doctrines of unity, which you might call the foundations of unity, in verses 4–6: “There is one body and one Spirit, just as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all.”
The practice of unity. Then, in verses 7–16, we’ll see the practice of unity and how it works out in the local church, particularly from verse 11: “And He gave some as apostles, and some as prophets, and some as evangelists, and some as pastors and teachers, for the equipping of the saints for the work of service, to the building up of the body of Christ; until we all attain to the unity of the faith, and of the knowledge of the Son of God.”

So that’s the big picture. Now let’s back up to the first few verses and look at the requirements for unity.

1. Unity Requires a Calling

First of all, unity requires a calling. Verse 1: “walk in a manner worthy of the calling with which you have been called.” And again in verse 4: “just as also you were called.”

This calling is, first, the effectual call of salvation. We see it, for example, in Acts 2:39: “For the promise is for you and your children and for all who are far off, as many as the Lord our God will call to Himself.” And we know that those who are called in that effectual sense cannot refuse the call, and they become children of God.

But beyond that: yes, we’ve been called, and yes, we are saved, but to what end has God done that? His call on our lives goes beyond just our ticket to heaven. There are other things we are called to. In the case of Paul, for example, Romans 1:1 says Paul was “called as an apostle.” So he was called to salvation, but he was also separately called as an apostle.

What I want us to see is that, in order to have unity, we need a common call. You might say a common mission. This is why, a few months ago, we spent time talking about the dominion mandate and the Great Commission. It’s when the church understands this divine mandate that the practice of unity becomes possible, because we are actually working together toward something. In Philippians 1:27 Paul says:

Only conduct yourselves in a manner worthy of the gospel of Christ, so that whether I come and see you or remain absent, I will hear of you that you are standing firm in one spirit, with one mind striving together for the faith of the gospel;

“One mind” there is basically the same idea as unity. Striving together: there was something they were working toward. They had an objective in mind, something they were seeking.

Sometimes this common mission can take the form of a common enemy. I think we all still remember so-called pandemic of 2020. You saw a spirit of unity among many churches of varied and diverse theology, because they were fighting the same enemy. (I’m speaking of the churches that actually stood up and did something.) And we all did this without compromising our distinctives. It allowed us to focus on a common purpose, in this case a common enemy, and therefore to have a real sense of unity in the church. Philippians 2:1–2 says:

Therefore if there is any encouragement in Christ, if there is any consolation of love, if there is any fellowship of the Spirit, if any affection and compassion, make my joy complete by being of the same mind, maintaining the same love, united in spirit, intent on one purpose.

They were to be of the same mind and united in spirit, and they were also intent on one purpose. They were going the same direction.

This is all the more important for those of us who embrace a postmillennial eschatology. If you’re premill or amill, you could, in theory, just ignore unity and wait for Jesus to show up, and it would take care of itself. I don’t mean to say that’s what they’re doing, but you could, and it would still all work out. That doesn’t work for us. If “the earth will be filled with the knowledge of the glory of the LORD, as the waters cover the sea,” that is going to require unity in Christ’s church. If we say Christ is going to win through His church rather than in spite of it, then we need unity. I believe I mentioned this verse already, but John 17:21: “that they may all be one; even as You, Father, are in Me and I in You, that they also may be in Us, so that the world may believe…” You see, the purpose of the unity Jesus prays for there is that the world may believe.

Babel reversed

As I considered examples of this point, my mind kept going back to something that may seem odd at first: the Tower of Babel. Let’s turn there briefly, Genesis 11. There is so much in these nine verses that connects to other parts of Scripture; I find myself thinking of Babel often because of those connections. Starting in verse 4, I’ll read a few verses:

They said, “Come, let us build for ourselves a city, and a tower whose top will reach into heaven, and let us make for ourselves a name, otherwise we will be scattered abroad over the face of the whole earth.” The LORD came down to see the city and the tower which the sons of men had built. The LORD said, “Behold, they are one people, and they all have the same language. And this is what they began to do, and now nothing which they purpose to do will be impossible for them. Come, let Us go down and there confuse their language, so that they will not understand one another’s speech.” So the LORD scattered them abroad from there over the face of the whole earth; and they stopped building the city. (Genesis 11:4–8)

So here God actually causes disunity, because they were using their unity for evil. God says there was nothing they would not be able to do on account of their unity. So God caused disunity to prevent them from accomplishing great things. But when it comes to His church, Babel is reversed. God wants unity, so that we can again do great things, through Him and for Him. Chapter 3 again: “Now to Him who is able to do far more abundantly beyond all that we ask or think, according to the power that works within us.”

So unity requires a calling, a mission.

2. Unity Requires Diligence

Number two, unity requires diligence. Back in Ephesians 4:3: “being diligent to preserve the unity of the Spirit in the bond of peace.”

To be diligent is to make haste, to exert oneself. It’s hard work. You don’t need diligence to do something easy. Unity is not something that just happens, or God wouldn’t tell us to use diligence in pursuing it. It’s going to be time-consuming.

I think we have a good example of this in the account in Acts 15 of what we call the Jerusalem Council. There was disunity in the church on account of certain teaching. And we see the elders and apostles of at least two different churches go to great lengths: travel, meetings, presumably many intense discussions, communications with various churches, and no doubt lingering conversations for months, explaining things to the holdouts or to the people who just missed the meeting. All things that are time-consuming and, frankly, pretty annoying. But they did this because they needed to do the hard work of seeking unity in the church.

We sometimes direct good-natured jabs at our Presbyterian brothers, who will spend inordinate amounts of time and effort doing exactly these kinds of things, adjudicating doctrine and practice in their churches. And while they may not get everything right, there is something good about the idea that when we have conflicts, they need to be hashed out and figured out, and we need to do all we can, as much as it depends on us, to come to a position of unity. For significant matters of doctrine or practice, it’s not good for these things to remain perpetually unresolved.

So unity requires diligence.

3. Unity Requires Preservation

Number three: unity requires preservation. “Being diligent to preserve.”

And here the plot takes a twist you might not have expected. We tend to think of unity as something to be fought for, or sought. Even as I’ve been speaking today, that’s more or less how I’ve been describing it. In a sense, that’s true: we do need to fight for unity and seek it out. However, Paul tells us here to preserve unity. So what exactly is going on?

If we consider where we’ve been in Ephesians already, we see that God is already building us into one temple. He’s already building us into one body. That is an objective reality, and we cannot stop or derail that plan. We are unified.

In fact, as I alluded to earlier in the service, when Jesus prays, what He prays for happens. To read the fuller context of His high priestly prayer in John 17:

“I do not ask on behalf of these alone, but for those also who believe in Me through their word; that they may all be one; even as You, Father, are in Me and I in You, that they also may be in Us, so that the world may believe that You sent Me. The glory which You have given Me I have given to them, that they may be one, just as We are one; I in them and You in Me, that they may be perfected in unity, so that the world may know that You sent Me, and loved them, even as You have loved Me.” (John 17:20–23)

When Jesus prays for unity, it happens. Jesus gets what He asks for. So there is already unity, and that is why we are told to preserve it. It’s as if Paul is saying, “You have unity; now act like it.”

Or we can put it another way: as Christians, we are never commanded to become one in Christ. We are simply told that we are one in Christ, because that is already an objective reality. Rather, we are told to make our subjective experience match the objective fact that already exists.

That being said, we are also to look ahead to greater unity and diligently pursue it, as I’ve already mentioned. We get a hint of this in verse 13 of chapter 4: “until we all attain to the unity of the faith.” So there is a sense in which there is still something future to strive for and attain more fully. But objectively, we are already unified.

There’s a good example of this in Philippians 4. We won’t turn there for the sake of time, but in Philippians 4:2–3, Paul says, “I urge Euodia and I urge Syntyche to live in harmony in the Lord.” And a verse later he speaks of those “whose names are in the book of life.” So these ladies are united in Christ. Objectively, they are unified; both are written in the book of life. But their present experience is not one of unity. They didn’t need to become unified, strictly speaking. They needed to exhibit the unity already achieved by Christ.

So unity requires preservation.

4. Unity Requires Truth

And fourth, unity requires truth. For this we’re cheating a little and going ahead to verse 13, which I read a moment ago: “until we all attain to the unity of the faith, and of the knowledge of the Son of God.” And then verse 14: “As a result, we are no longer to be children, tossed here and there by waves and carried about by every wind of doctrine.”

So we see that unity actually has a lot to do with truth: “the unity of the faith, and of the knowledge of the Son of God,” so that we are no longer “carried about by every wind of doctrine.”

Unity is not achieved by subtraction

This goes against what many people wrongly assume, which is that we achieve unity by subtraction. People think we just take away the things we disagree about so we can have unity. That is precisely backwards. It’s the mistake all the so-called “united” churches make. As soon as that word is your denomination or the name of your church, the way it always seems to work (show me an example to the contrary) is that we unite by stripping away all the differences and uniting on what I earlier called minimalist theology.

The problem is that this actually takes away the opportunity for unity, because you cannot unite around nothing. There’s no unity in believing nothing. Even non-religious organizations understand this. Think of fraternal orders, like the Elks Lodge or the Shriners. They end up creating some kind of objective something they’re supposed to be working toward, some greater good, because they need something to unite around, something to hold things together so they can move forward.

Our church constitution

I was working this week on our church constitution, and it touches on this same issue. This is just wording we’re working with; it’s still a draft. But the draft presently speaks of our unity in the context of the creeds. There are the three ecumenical creeds we subscribe to, one of which, the Apostles’ Creed, we confess every Sunday. The draft says:

We hold to the ancient ecumenical creeds as articulating the faith once for all delivered to the saints, and we hold that no one rejecting the truths proclaimed in these creeds can be right with God.

You might call that the minimal part. But that’s the creed; what’s in those creeds is absolutely paramount.

Then it talks about our confession. Our confession is the Savoy Declaration; similar confessions are the London Baptist Confession and the Westminster Confession. These are documents that go to great length to articulate biblical theology: how we should properly understand the Scripture. Speaking of the confession, the draft says:

We hold to the distinctive truths of our confession. Knowing that many faithful Christians have differed with portions of this confession, we confess our view that our confession faithfully represents Scripture, but we do this not as a means of dividing with Christians who differ, but to make a faithful testimony of what we believe Scripture teaches.

You see, even with the confession, the goal ultimately is to make a faithful testimony of what the Scriptures teach. Not for the purpose of division, but ultimately for the purpose of unity, and of seeing more and more like-mindedness in the church.

Diversity is not our strength

And this brings up an interesting topic: diversity. There’s always talk about diversity, that “our strength is in our diversity,” and other silly things like that, whether in the context of diversity of race, diversity of religion, diversity of culture, or whatever it might be. None of those are actually a strength. And likewise, theological diversity is not our strength. We should realize that theological diversity among Christians is, by definition, due to our lack of conformity to Christ. To the degree that we have theological diversity, it’s because some of us are not properly conforming our beliefs to Christ.

This is why I’m not a big fan of another terrible platitude: that we should just “agree to disagree.” Now, I know that usually when people say that, what they’re communicating is fine. It’s a way of saying, “We’re not going to argue about that today.” And that’s okay. We don’t argue about everything every day; that’s totally fine. But the goal should not be simply to agree to disagree in perpetuity. The goal should be to work through those things and, as a church, to come to a unified position as much as possible.

Who is the divisive person?

I want to make one other point about unity and truth, and then we’ll bring this to a close. There are many warnings in Scripture about being divisive. And I think we often picture the divisive person as someone who speaks in the wrong tone, or who just has different ideas about something. And they might. They might have some silly ideas, and they might talk in the wrong tone; that’s very possible. But ultimately, when we see the divisive person in Scripture, what makes them divisive (and the reason we’re talking about it under this point) is that they are wrong. The divisive person is the one teaching something that is wrong. Romans 16:17:

Now I urge you, brethren, keep your eye on those who cause dissensions and hindrances contrary to the teaching which you learned, and turn away from them.

The person causing dissension and hindrance is the person teaching contrary to Scripture. And in 3 John 9 the apostle says:

I wrote something to the church; but Diotrephes, who loves to be first among them, does not accept what we say.

There was obviously an issue of pride as well: “who loves to be first among them.” But it explains his divisiveness: he “does not accept what we say.”

Next week we’ll discuss some counterpoints to this. We’ll be talking about humility, gentleness, and patience. This doesn’t mean we go around bludgeoning people with the Scripture or arguing over every item all the time. But truth is something that must be preserved. And it is only through our focus on what is true that we can have any kind of lasting and substantial unity. Again, without believing something, there is no unity. We absolutely do not obtain unity by reducing the things we believe.

So next week we’ll continue our study and look at the tools for unity. But we’ll stop there for today. Let’s pray.

Jesus, You prayed that we would be unified, in order that Your love might be displayed to the whole world. Lord, we know that Your plans will not be thwarted. We know that what You ask, You will receive, and we thank You that Your church is one. And Lord, we pray that we might diligently work to preserve the unity You have, in fact, already delivered to us. It is in Your name that we pray. Amen.

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