17:20 “I am not praying only on their behalf, but also on behalf of those who believe in me through their testimony, 17:21 that they will all be one, just as you, Father, are in me and I am in you. I pray that they will be in us, so that the world will believe that you sent me. 17:22 The glory you gave to me I have given to them, that they may be one just as we are one—17:23 I in them and you in me—that they may be completely one, so that the world will know that you sent me, and you have loved them just as you have loved me.

‘It is a union in spiritual life; a union in faith in a common Saviour, in love to his blessed name, in hope of his glorious appearing.’ (David Brown)

Its:-

1. Apostolic foundation, v20; cf. Eph 2:19f ‘built on the foundation of the apostles’; 1 Jn 1:3 Jude 3, ‘the faith that was once for all entrusted to the saints.’

2. Divine origin, v21f; cf. Acts 4:31f. ‘They were filled with the Holy Spirit and spoke the word of God bodly. All the believers were one in heart and mind.’ We do not and we cannot create this unity.

3. Universal scope, v21; cf. Jn 10:16 “I have other sheep that are not of this sheep pen. I must bring them also…And there shall be one flock and one shepherd.” This does not mean, of course, that true unity can exist between all who call themselves Christian, for that word can mean different things to different people. There must be agreement on at least the fundamentals of the faith. And yet it will always be to some extent an imperfect unity, for we cannot judge the hearts of men. There will always be questions about the extent to which we can associate with those whose Christian profession is compromised, either by doctrinal or practical error. But we are to adopt an attitude like that of our Master, and seek prayerfully to build up true Christian unity.

4. Heavenly pattern, v21; cf. Jn 1:1,18.

‘The idea of the divine unity, which has been given generally before (v11, and v22), is set out in detail in its correlative manifestation…There is, so to speak, an interchange of the energy of the divine Life (“thou in me, and I in thee”), which finds a counterpart in the harmonious relations of the members of the Church.’ (Westcott)

The union between Christ and his people ‘is compared to the union between the vine and the branches; to the union between the head and the other parts of the body; to that between the foundation-stone and the other parts of the building; and also to that between husband and wife – all most precious and significant emblems. But here, most wonderful of all, it is compared to the mysterious union between the Father and the Son.’

5. Distinctive love, v21; cf. Jn 13:34-35; 1 Cor 13:4-7.

‘The unity of believers will be explicable to the world only on the basis of divine love. It will transcend all human unity. The unity in question, while it is a spiritual unity rather than one of organisation…yet has an outward expression, for it is a unity which the world can observe, and which will influence the world.’ (Leon Morris)

6. Practical outworking, v21.

‘Far be it from us to advocate a mere external union, at the expense of the great fundamental truths of the Gospel; nothing could be farther from our mind. But is it not truly lamentable to hear men sometimes magnify their own particular crotchets, which, of course, never had any place in the Word of God, into important principles; and so rending asunder the body of Christ. Surely nothing could be at more variance with the prayer of the Saviour.’ (Ross)

7. Effective witness, v21; cf. Jn 13:35. This unity is not simply a positional thing; it is meant to be worked out in a practical and visible way.

‘The size and extent of the Church alone will not impress the world. This inward unity expressing itself in a common mission and message will alone impress the world.’ (Strachan)

‘The spiritual effect wrought in Christians, the visible manifestation of a power of love among them…is declared to be a sufficient proof of the divine mission of him from whom it comes, and of the continuance in them of the divine working. This working is not however such as might have been anticipated. The life of believers shews the same contrasts of joy and apparent failure as the life of Christ. But those contrasts are no disparagement of the perfectness of the love of God towards them.’ (Westcott)

8. Progressive nature, v23; cf. Eph 4:1-6.

‘We can ask no stronger proof of the value of unity among Christians, and the sinfulness of division, than the great prominence which our Master assigns to the subject in this passage. How painfully true it is that in every age divisions have been the scandal of religion, and the weakness of the Church of Christ! How often Christians have wasted their strength in contending against their brethren, instead of contending against sin and the devil! How repeatedly they have given occasion to the world to say, “When you have settled your own internal differences we will believe!”‘ (J.C. Ryle)

This unity should be expressed within the local church. The local church is diverse in its membership: men and women, young and old, mature and immature, rich and poor, educated and unsophisticated, leaders and members, to say nothing of the rich array of spiritual gifts which the Lord apportioned to each one as he wills. There is a great danger of individualism. Too many people want their own way. ‘Hell hath no fury like a personal preference masquerading as a theological principle.’ We are called to seek the common good.

This unity should be expressed within the worldwide church. The practical outworking of this is complex and problematic. But there is an attitude to be avoided which simply engages in ritual denunciations of other groups of Christians. And there is an attitude to be adopted which is a reflection of and a response to this prayer of Christ: ‘that all of them may be one.’