Jesus’ prayer for unity in his Church
John 17 is holy ground: Jesus prays for unity, that his Church may be one. For this is the key to effective mission. It is a passage which has often been misunderstood and mis-preached.
I recall hearing a church leader say that the most serious cause of failure to evangelize our country was disunity within Christ’s church. Referring to Jesus’ prayer recorded in John 17, he pointed to Christ’s ardent desire for unity amongst his disciples, and the close connection between such unity and effective mission (17:21).
This raises the question of what exactly Jesus was saying, and leads us back to the text to investigate. In John 17 it is obvious how important unity is - three times Jesus prays for it (vv 21,22, 23) – so we are bound to ask ‘Who is such unity to be between?’ ‘What kind of unity is meant?’ and ‘What could be the connection between unity and effective mission?’
In a series of expositions from what we know as the Upper Room Discourse, delivered to the North American student missions convention in Urbana, John Stott brought a note of caution. These prayers, so often quoted, had, he said, come to be the proof texts of the ecumenical movement. It was important to understand their context if we are to interpret them correctly, and not be unbalanced, or even mistaken in their interpretation. He went on to urge ‘careful and critical scrutiny.’ 
Here we attempt to give them that scrutiny, for a study of these words offers far-reaching implications for church and mission today.
The structure of Jesus’ prayer is straightforward - first he prays for himself (see v1-5), then for the disciples (v6-19) and finally for ‘those who will believe through their testimony’ (v20-26). The content of the prayer however varies. Now that Jesus’ hour has finally come, his prayer for himself is that he might be glorified in carrying out his Father’s will, with all the suffering that will entail. Turning to pray for the disciples, Jesus asks that they might be sanctified (set apart) for, and by, the truth - the truth that is found in God’s word – for this is how they will be able to withstand the enmity of the world. It was to this group of eleven, soon to be apostles, that Jesus had already made promises about the gift of the Holy Spirit. For the Holy Sprit would enable them to recall all that he had taught them, and lead them into all that truth which they were not yet able to embrace (see 14:26, 16:8-11). Although Jesus prays that the apostles may be ‘one, even as we are one’ (v11) it is not until the third phase of his prayer that his petitions focus chiefly on unity. So let us look at 17:20-26 in greater detail.
‘I do not ask for these only, but also for those who will believe in me through their word’ (v20). As Stott pointed out to the students, ‘Here Christ distinguishes between the apostles for whom he has just been praying and those who would later believe in him through their teaching.’ This distinction is vital if we are to make sense of what follows. Stott emphasizes the point:
‘Jesus alludes to two groups, conveniently designated “these” (i.e. the apostles) and “those’” (i.e. subsequent believers). It seems beyond question that the “all” of v21, whose unity Christ desires, are a combination of “these” and “those”. Let me elaborate on this. The Lord Jesus peers with prophetic eyes into the future. He sees generation after generation of his followers. He calls them “believers”, for they will believe in him, and they will believe in him through the apostles’ words. This is a description of every single Christian believer from the Day of Pentecost onward, including ourselves... here then are the two groups - the little band of chosen apostles (“these”) and the huge company who will believe in Jesus through their word (“those”). And Christ’s prayer is that “all” (both “these” and “those”) may be one.’
Let’s pause a moment, and not miss this. Jesus is first and foremost asking his Father for unity between the apostolic church of the first century and the church of subsequent centuries. He is praying that we might believe the same truths, follow the same Lord, proclaim the same message, obey the same teaching, suffer for the same cause and share in the same hope. This is in accord with the description of the first converts who, Luke tells us, ‘devoted themselves to the apostles’ teaching and fellowship’ (Acts 2:42). As a result of the fulfillment of Jesus’ promises to them the New Testament was written, which makes it possible for every subsequent generation to devote themselves similarly to the teaching of the Apostles. Here then is the kind of apostolic succession envisaged by Jesus. This is the unity for which he prayed.
A further aspect of that unity is articulated in the second half of v21, ‘that they also may be in us.’ Jesus’ eternal fellowship with the Father shows the pattern for the relationship between the church and the Godhead. It speaks of an organic unity. Again Stott put it helpfully, ‘The unity of the church for which Christ prayed was not primarily that we may be one with each other, but first that we may be one with the Apostles, and second that we may be one with the Father and the Son. The first speaks of a common truth, the second of a common life. And both are needed to unite the church.’
So the means of establishing and maintaining unity is common truth. Far from the popular notion that doctrine divides, Jesus taught the opposite - unity amongst the apostles would be secured by their loyalty to the divine revelation (v11), and unity in the later church would be secured in the same way. Stott insists, ‘It is not by neglecting Christ or the apostolic witness to Christ that the church’s unity will be secured. Rather the reverse. The unity of the church is unity in the truth.’ To quote Hugh Latimer: ‘Unity must be according to God’s holy word, or else it were better war than peace. We ought never to regard unity so much that we forsake God’s word for her sake.’ 
What then of the connection between unity and mission? In all that Jesus prays, the purpose of this kind of unity is missiological, ‘so that the world may believe’ (v21, v23). They will always be closely linked as evangelism is central to the calling of the whole Church. Indeed it is the very object and purpose of this unity. So we must all work to maintain this unity until the ultimate goal of Heaven is reached (v24).
We conclude with John Stott’s summary: ‘So truth, holiness, unity and mission belong together and cannot be separated.’
Alan Purser, recently retired from Crosslinks.
This article forms an Appendix to ‘The Reformation: What you need to know and why’ by Michael Reeves and John Stott (Hendrickson Publishers / Monarch Books). Complete work copyright 2017 Lausanne Movement. Used with permission.
 John Stott’s addresses (1964). See urbana.org for its growing video archive
 Latimer’s second sermon preached in the county of Lincolnshire (Sermons Vol 1 p 487)