The psalmist exclaimed, “Behold, how good and pleasant it is when brothers dwell in unity!” It was no mean task to bring together the warring tribes of Israel. But it was worth the effort, for the unity of God’s covenant people is beautiful. So beautiful, in fact, that our Savior laid down His life to redeem and purify “a people for his own possession” (Titus 2:14). That “people” is emphatically singular.

Nowhere is that singularity more clearly taught than in John 17, where our Lord prayed about what He would accomplish by His death on the cross. In His High Priestly Prayer, He asked His Father to glorify Him (vv. 1-5), to keep His disciples (vv. 6-19), and to unify His Church (vv. 20-26). Three times in verses 21-23 He prayed that those who believe in Him might be one. The implications of this prayer are immense, and coming to terms with them is deeply challenging.

I can think of three very different situations when the immensity of this prayer has been impressed upon me—three very different settings in which I have preached the Word of God. One was an African American congregation in Pittsburgh, Pa. Another was a Hungarian Reformed mission church among the Roma people of the Trans-Carpathian Ukraine. The third was a chapel service at Chongshin University in Seoul, South Korea. In two of these settings I preached through a translator. The cultural, ethnic, and linguistic differences were enormous. Yet in all three places I discerned a deep sense of unity among brothers and sisters in Christ. This is the spiritual unity for which Christ prayed in these verses.

This spiritual unity is broad and deep. Its implications reach out not only to the congregation of which we are members or the denomination of which we are a part. It is not even about the broader theological tradition within which we may identify ourselves, such as Reformed or Evangelical Protestantism. Our Savior prays that “all may be one.” Let’s consider what that means, and then work out what we do about it.

Godlike Unity (vv. 20-21)

The model upon which the unity of the Church is patterned is nothing less than the inner life of the triune God. In verse 20, our Lord broadens the focus of His prayer from the twelve apostles to “those who will believe in me through their word.” Those who believe the apostolic gospel are not only delivered from sin and death but also caught up into the mission of the triune God. To this end our Lord prays that those who believe “may all be one, just as you, Father, are in me, and I in you, and that they may also be in us.”

The inner life of the triune God is reflected in the mission of God. God the Father sent His Son into this sinful world for a purpose. The Son gave Himself in perfect agreement with His Father’s purpose. Our Savior prayed that the world might see that purpose worked out as sinners are saved and gathered into the Church. Unity of purpose arises from God’s people getting on board with the redemptive mission of the triune God.

One very practical implication of this is that Church unity is realized as we learn to play our part in God’s mission. Mission is something we do together. Church members blend their diverse talents and energies in pursuit of the Great Commission. Christians contribute to the unity of the Church as they evangelize their communities through the congregation of which they are members. They deepen that unity as they support other congregations in their witness. Their work is our work as well. Sitting on the sidelines while others labor, or focusing inward, works against the unity for which our Savior prayed.

Glorious Unity (vv. 22-23)

These verses describe the positive witness that the unity of the Church presents to the world. Our unity is a reflection of the very being of the triune God. In verse 22 our Savior’s prayer takes up one aspect of God’s character—His glory. Jesus has already prayed that His Father would glorify Him in verses 1-5. His prayer was answered as the Father sent Him into the world surrounded by His love and sustained by His power (John 1:14; 2:11; 8:54; 11:4; 16:14). Now Jesus takes that glory and gives it to His disciples. This is the glory that activates or enables the unity of the Church. Note the driving purpose in John 17:21. Jesus states that He has given His glory to His Church “that they may be one, even as we are one.”

It is important to pause and consider what this glory actually is. We are often told that God’s glory in the Old Testament is weighty. It is so heavy that you can feel its presence. The word for glory in the New Testament has a somewhat different significance. It is so bright that you can see it. In fact, you cannot miss it. Unity is the visible manifestation of the glory that Christ gives His Church. And so, as a result of this gloriously visible unity, the world can see the love of the Father for the Son. That love is reflected in us as we love one another.

That is why Francis Schaeffer called the love Christians have for each other “the ultimate apologetic.” It is our most eloquent declaration of the love of God that stands at the heart of the gospel message. John 3:16 only makes sense to people around us when they can see that we love each other. Are we sometimes disappointed when our evangelistic ministries do not bear fruit? Perhaps we need to ask whether those we seek to reach can see in us the visible glory of Christian love for the body of Christ.

Perfect Unity (vv. 24-26)

In these verses our Savior does not specifically mention the oneness of believers. However, this vitally important theme cannot have been far from His mind as He brings His prayer for the Church to its climax. When His disciples were distressed at the prospect that He would leave them, He calmed their troubled hearts by promising that He was going to prepare a place for them. After His work was complete He would come again “that where I am you may be also” (John 14:1-3).

In John 17:24 our Lord takes up that promise as He explains that, when He gathers His whole family into His presence, they will see His glory. This will be even greater than the glory He gave them in verse 22, for this is the glory He had in the presence of His Father before the foundation of the world. The plan of redemption comes full circle as Father and Son, together with the Church, enjoy unending and untroubled fellowship.

This blessed fellowship is something the world does not understand because it does not know the Father. With eager anticipation the Son of God cried out to His Father, “O righteous Father, even though the world does not know you, I know you, and these know that you have sent me. I made known to them your name, and I will continue to make it known, that the love with which you have loved me may be in them, and I in them” (v. 25). This is the climax of Church history. Perfect unity in perfect fellowship with the triune God.

This perfect love is beyond our capacity to imagine or exercise here on earth. Yet eschatology always empowers Christian living. It helps us to put our here-and-now struggles and failures in context, and it enables us to see what God has stored up for us. Our churches have been planted by Christ in this fallen world so that they might give a foretaste of heaven. They are to offer the world a foretaste of this perfect unity, even as we grapple with our tensions and divisions.

Conclusion

So, how do we grapple with our divisions? We need to recognize that, in this prayer, our Savior is not just praying for the Reformed Presbyterian Church. He is praying for the whole Church, and that includes people with whom we might be uncomfortable rubbing shoulders within a worship service. Perhaps for good reasons. While we disagree with some of their theology, we are on the same team. That is a core component of our ecclesiology.

We need to recognize the danger of a lazy tribalism as we think about the worldwide Church. How, then, do we engage with the wider Church? How do we give legs to our ecclesiology? We have to begin somewhere. We begin with the saints we know. In the next article we will face up to that challenge.

Andrew Stewart was born into a Reformed Presbyterian family in Northern Ireland. In 1990 he was ordained minister of the Glenmanus (N. Ireland) RPC where he served for eight years. Responding to the call of the Geelong (Australia) RPC, he moved with his family to Australia in 1998. He continues to pastor that congregation as well as lecture at the Reformed Theological College in Australia.