(21) That they all may be one--i.e., both "these" (the Apostles) and "them also which shall believe on Me through their word" (the whole body of believers in all times and places). He expresses in this grand thought of the unity of the whole Church the fulness of the purpose of His prayer.

As thou, Father, art in me, and I in thee, that they also may be one in us.--The insertion of "art," which, as the italics show, is not in the original text, weakens the sense. It is better, therefore, to omit it. The word "one," in the second clause, is of doubtful authority, and has the appearance of a gloss. The probable reading, therefore, is, That they all may be one; as Thou, Father, in Me, and I in Thee, that they also may be in Us; and the meaning is that the union of the Church may be of the same essential nature as that between the Father and the Son; yea, that the union of the Church may result from the union of individual members with the Father through the Son. (Comp. John 14:23; John 15:4-10, et al.) The Father in the Son and the Son in the Father; both Father and Son taking up their abode in the believer, and the believer, therefore, in the Father and the Son. This is the ideal of the unity of the Church of Christ; and if this union with God is realised by each individual, it necessarily follows that all the individuals will be one with each other. (Comp. Notes on Ephesians 4:4 et seq.)

That the world may believe that thou hast sent me.--The result of the union of believers with God, and therefore with each other, will be that the world will see in it a proof of the divine origin of Christianity, and will believe that the Father sent the Son into the world. As this will be the result, it is thought of as the purpose of the prayer for the whole body of believers. Instances of this result crowd involuntarily upon the mind. The brotherhood of Christians has ever been the witness to their common Fatherhood in God. The divisions of Christendom have ever been the weakness of the Church and the proof to the world that, in that they are divided, they cannot be of God. (Comp. Note on John 13:35.)

Verse 21. - That they all may be one. My prayer is that the many may become one, form one living glorious unity; - every part of which spiritual organism, while living a separate and differentiated life, is yet a part of a whole. In the natural sphere, as the parts of a whole organism are mere and more developed, and increasingly resemble individualities in their separation, they are in the same proportion dependent on the whole for the life that is in them. Even in a highly organized community, as the separate individuals have more and more personal consciousness of special function, they become the more dependent on the whole, and in one sense lost in the unity to which they belong. The branches in the vine form together one vine; the members of a body, being many, are one body and members of one another. It is open to discussion whether the καθὼς clause, which here follows, characterizes the above statement, as Meyer and many others urge, or whether, with Godet, the sentence, "That they all may be one," should not be taken as a general statement, to be followed by the καθὼς clause, which characterizes the following words. The first method is a more rational interpretation, nor does the sentence drag. According as thou, Father, (art) in me, and I (am) in thee; i.e. the relation between the Father and Son, the manner in which the Father lives in the Son, as in his organ or instrument of manifestation and object of supreme affection, and as the Son is in the Father, abiding ever in the light of his glory, in the power of his Name, and as these two are thus One in being, so, or similarly, the believers are to live in and for each other, becoming a unity, just as the Father and Son are unity. In order that they themselves also may be [one] in us. This ἵνα does not offer a parallel sentence in apposition with the former, nor is the "that" to be inverted, with Godet, who translates, "that according as thou.., they also may be one in us;" but it is the climax of the whole unifying process, after the likeness of the union between the Father and the Son, viz. that they themselves may be included in this unity. Though they are thus to be lost in God, yet they do not lose their own individuality. Nay, in proportion to their organic relation to the fullness of the Godhead and the completeness of their own spiritual fellowship with one another, will this personal consciousness of theirs become more and more pronounced. There is yet a further process contemplated, viz. in order that the world may believe (πιστεύῃ, as in the next verse; γινώσκῃ, in the present subjunctive, rather than the aorist) that thou didst send me. The spiritual life and unity of the Church will produce an impression on the world which now rejects the Christ and does not appreciate his Divine commission. The union which springs from the blended life of the various and even contradictory elements in the Church will prove the reality of its origin. The world will believe, - this is the final purpose of the intercession concerning the disciples; so though above he did not pray for the world as the then immediate object of his intercession, the poor world is in his heart, and the saving of the world the end of his incarnation. If the union between the Father and the Son is the sublime type of the union between those who shall believe, it is not the union of a great society in accordance with certain invincible rules of affiliation and government. The union between the Father and Son is not a visible manifestation, but a spiritual inference. The common indwelling in the Father and Son, the identity of the spiritual emotion and purpose in all who have one Lord, one faith, one baptism, will convince the world by producing a similar inference. Alford: "This unity is not mere outward uniformity, nor can such uniformity produce it. At the same time, its effects are to be real and visible, such that the world may see them."

17:20-23 Our Lord especially prayed, that all believers might be as one body under one head, animated by one soul, by their union with Christ and the Father in him, through the Holy Spirit dwelling in them. The more they dispute about lesser things, the more they throw doubts upon Christianity. Let us endeavour to keep the unity of the Spirit in the bond of peace, praying that all believers may be more and more united in one mind and one judgment. Thus shall we convince the world of the truth and excellence of our religion, and find more sweet communion with God and his saints.That they all may be one,.... Among themselves. This may regard their unity in faith, and in the knowledge of Christ; for there is but one faith which all truly experienced souls agree in: they are converted by the same Spirit, and have the same work of grace wrought in them; and though they have not the same degree of light, and measure of spiritual knowledge, yet they agree in the main point of the Gospel, salvation alone by the Lord Jesus Christ; and such an agreement in the doctrine of faith, and the grand articles of it, respecting the person and offices of Christ, is absolutely necessary to their comfortably walking together in church fellowship, and the more honourable carrying on the worship of God together; and which will be more manifest in the latter day, when saints shall see eye to eye: likewise an unity in affection may be here designed, a being knit together in love to each other; which is the bond of perfectness, the evidence of regeneration, the badge of the Christian profession, the beauty of church communion, and the barrier and security from the common enemy; and without which, social worship and mutual service will be either neglected or coldly performed. Moreover, this petition may have respect to the gathering together all the saints at the last day, as one body united together in faith and love; as one general assembly and church of the firstborn; as one fold of which Christ is the head, Saviour, and shepherd:

as thou, Father, art in me, and I in thee. There is a mutual in being of the Father and the Son, who are one in nature and essence, in power and will, and in understanding and affection; which union, though it infinitely transcends any kind of union among men, or that can be conceived of by men, yet is the exemplar of the saints' union one with another, and to the divine persons; and which must be understood not of an equality, but a likeness:

that they also may be one in us: there is an union of all the elect to God and Christ, which is already complete, and not to be prayed for; they are all loved by God with an everlasting love, by which they are inseparably one with him; they are all chosen in Christ, as members in their head, and are federally united to him, as their Mediator, surety, and representative; in consequence of which he has assumed their nature, stood in their place and stead, and brought them nigh to God. There is a manifestation of union in conversion, when persons openly appear to be in Christ; and as a fruit and effect of everlasting love, are with loving kindness drawn unto him; and which will be more gloriously seen, when all the elect shall be brought in, and God shall be all in all, and is what Christ here prays for:

that the world may believe that thou hast sent me; either the rest of God's chosen people in the world, not yet called; or rather the wicked and reprobate part of the world, particularly Jews and Deists: they shall see the concord and agreement of the saints in doctrine, worship, and affection in the latter day; and when all the elect shall be gathered together, and not only their union to each other, but to the divine persons, shall clearly appear; they will then believe, ant be obliged to own, that Jesus is the true Messiah, was sent of God, and is no imposter.