Why is unity in the church so hard? If you’re like me, this question can prompt tears.

Mentioning tears tells you I’m not talking about disunity in the church in general. I’m talking about disunity in churches we know and love, and between Christians we know and love.

And for the most part, I’m not talking about disunity fueled by higher-level disagreements over primary Christian doctrines (ones that define the bounds of Christianity) or even secondary doctrines (ones that define, say, the bounds of a denomination). I’m talking about the far more common kind of disunity fueled by the endless variety of conflicts that break apart relationships, and even whole churches, because earnest, sincere Christians fail to humbly, gently, patiently “[bear] with one another in love” and cease being “eager to maintain the unity of the Spirit in the bond of peace” (Ephesians 4:1–3).

If you’re like me, you’ve seen too much of this, and you wonder, sometimes with tears, “Why is unity in the church so hard?”

But, if you’re like me, this question might also reveal misguided assumptions we have about what Christian unity is supposed to be like. What I found lurking behind my question (and I don’t think I’m unusual here) was this assumption: unity between Christians who love and trust Jesus, are filled by his Spirit, and largely agree theologically, should not be this hard. It seems reasonable on its face. But a reasonable assumption doesn’t make a right assumption, especially when the Bible doesn’t support it.

Unity Has Always Been Hard

Don’t get me wrong: God is all for unity between God’s children. Scripture describes the experience of unity as “good and pleasant” (Psalm 133:1), and it commands all Christians to diligently pursue “being of the same mind, having the same love, being in full accord” (Philippians 2:2).

“The Bible nowhere promises that the pursuit of unity won’t be as hard as it often is.”

But nowhere in the Bible does God promise that the pursuit of unity, even among real, Spirit-filled, earnest Christians, won’t be as hard as it often is — any more than it promises that battling our indwelling sin won’t be as hard as it often is, or that suffering won’t be as devastating as it is, or that the whole endeavor of Christian love (of which pursuing unity is one aspect) won’t be as costly and humanly impossible as it is.

If anything, the fact that the New Testament records so many Christians struggling and failing to be unified should tip us off that unity is anything but easy. We only need to read through the letters of Paul to see this. Here’s just a small sampling of how often he addresses the issue of unity:

• He reproves the Corinthians for their “quarrelling” and “divisions” (1 Corinthians 1:10–11).
• He warns the Galatians against the dangers of “rivalries, dissensions, divisions” (Galatians 5:20).
• He entreats “Euodia and . . . Syntyche [in Philippi] to agree in the Lord” and pleads with others to intervene (Philippians 4:2).
• He instructs the Colossians, “Forgive each other as the Lord has forgiven you” (Colossians 3:13).
• And he exhorts the Ephesians not to indulge in “corrupting talk” so as to “not grieve the Holy Spirit of God,” and to put away “all bitterness and wrath and anger and clamor and slander . . . along with all malice” (Ephesians 4:29–31).

I could quote many more. Which is why I say that the Bible doesn’t support our assumptions that Christian unity shouldn’t be as hard it is to attain and maintain. It’s been this hard since the earliest days of the church.

Why Unity Is Hard

Okay, so God doesn’t promise that unity won’t be hard — and, apparently, it’s always been hard. But that still leaves us with the question, “Why is unity in the church so hard?”

There are, of course, an endless number of factors. Consider that at any given time a church may be under heavy spiritual assault (Ephesians 6:12), infiltrated by wolves in sheep’s clothing (Acts 20:29), plagued by “rivalries, dissensions, divisions” stirred up by unbelievers who think they’re Christians (Galatians 5:19–21), trying to tempt immature believers to engage in partisan quarrels (1 Corinthians 3:1–4), and on and on.

But I’ll give two important high-level reasons we glean from Scripture for why unity in the church is as hard as it is — indeed, why, for our ultimate joy and his glory, God designed it to be as hard as it is.

Our Unity Refines Us

Scripture tells us that Jesus “himself bore our sins in his body on the tree, that we might die to sin and live to righteousness” (1 Peter 2:24). In other words, Jesus’s substitutionary, atoning death purchased the gift of our forgiveness (he “bore our sins”) and the gift of our holiness (“that we might die to sin and live to righteousness”). Our holiness is a gift of God’s grace. Which means anything God designs to transform us into the likeness of his holy Son is a great gift. But sanctifying gifts tend to arrive in painful packages, because learning to die to sin and live to righteousness is almost always hard and often painful.

“Our pursuit of unity is designed to give us many opportunities to die to our own sin and bear with the sin of others.”

That’s why “maintain[ing] the unity of the Spirit in the bond of peace” (Ephesians 4:3) is usually hard. Paul says it requires that we “put off [our] old self, which belongs to [our] former manner of life and is corrupt through deceitful desires” — die to sin — “and to put on the new self, created after the likeness of God in true righteousness and holiness” — live to righteousness (Ephesians 4:22–24). Our pursuit of unity is designed to give us many opportunities to die to our own sin and bear with the sin of others.

Our Unity Exalts Christ

What image comes to mind when you hear Jesus’s words, “By this all people will know that you are my disciples, if you have love for one another” (John 13:35)? I tend to imagine some kind of idyllic Christian community of love — a kind of Christian community I’ve never seen, even in Scripture, even in those first sweet chapters of Acts.

What image did Jesus have in mind? We can see it in the previous verse: “A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another” (John 13:34). Jesus was about to “lay down his life for his friends” (John 15:13). And he told his friends (all of us) to love one another “just as I have loved you.” Jesus was envisioning a cruciform community of Christians whose sacrificial love for one another frequently required them to take “the form of a servant,” pick up their cross, and “count others more significant than [themselves]” (Philippians 2:3, 7).

The pursuit of unity is hard because the love of God is costly. The love of the Father and the Son was most clearly and climactically displayed on the cross, and so our love for one another is designed to publicly display Godlike love in the world. “By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers” (1 John 3:16). That’s how all people will know we’re Jesus’s disciples.

Never Give Up

The pursuit of Christian unity in a local church is a high calling. It’s a means of our growing in Christlikeness through sanctification, and it’s a means of proclaiming the otherworldly love of Christ through demonstrating the otherworldly love of Christ in a love-starved world.

It can be a heartbreaking pursuit in view of how often we fail. But let’s keep it in perspective. It’s no less surprising that we too frequently fail to maintain the unity of the Spirit in the bond of peace, than that we too frequently fail to continually abide in Jesus (John 15:4), strive for holiness (Hebrews 12:14), pray without ceasing (1 Thessalonians 5:17), love our enemies (Luke 6:27), bless those who persecute us (Romans 12:14), or count it all joy when we experience various trials (James 1:2).

Let’s not allow our failures to obey to become excuses to keep disobeying. Let’s put the 1 John 1:9 grace of God on public display by confessing and repenting of our sins and receiving God’s and one another’s forgiveness. And then let’s put the tenacious, gracious love of God on display by resolving to never give up, “so far as it depends on [us]” (Romans 12:18), seeking to “maintain the unity of the Spirit in the bond of peace.”

Christian unity is a high call, and a hard call. In fact, it’s impossible apart from “the help of the Spirit of Jesus Christ” (Philippians 1:19), for apart from him we can do nothing (John 15:5). But that’s the way it’s supposed to be. For unity is not about fulfilling our idyllic expectations, but about displaying the reality of the redeeming, sanctifying love of God.