My critique goes for whatever the official teaching is of the Trinity. It won’t stand up to John 17:22 (“as we are one”). If the official teaching is “One Divine Substance, Three Persons”, so be it. There is no way that Christ’s mortal disciples will ever become united in the sense that they become separate persons of a single divine substance the way that The Father and the Son are united per the Trinitarian belief. Case closed.
"What Jesus asks for them is unity—a unity of souls, imitative of the Divine Trinity (and, no doubt, a social unity of bodies in which St Cyril sees the effect of the Holy Eucharist)—a unity which will be a proof to the world that God is here.
Leonard, W. (1953). The Gospel of Jesus Christ according to St John. (B. Orchard & E. F. Sutcliffe, Eds.)A Catholic Commentary on Holy Scripture (p. 1010). Toronto: Thomas Nelson.
The Internal Unity of the Church. A common proverb says: “Many heads, many minds”; but the first Christians proved the fallacy of the saying. The Christian flock counted many thousand heads, but they were all of one mind, as if they had one heart and one soul. This wonderful unity was the work of the Holy Ghost, whose grace changed the hearts of the faithful, and made them all ready to obey the Apostolic teaching. Thus was granted the prayer of our great High Priest for His Church: “I pray that all may be one, that the world may know that Thou hast sent Me” (John 17:21).
Knecht, F. J. (1910). A Practical Commentary on Holy Scripture (p. 747). London: B. Herder.
820 “Christ bestowed unity on his Church from the beginning. This unity, we believe, subsists in the Catholic Church as something she can never lose, and we hope that it will continue to increase until the end of time.” Christ always gives his Church the gift of unity, but the Church must always pray and work to maintain, reinforce, and perfect the unity that Christ wills for her. This is why Jesus himself prayed at the hour of his Passion, and does not cease praying to his Father, for the unity of his disciples: “That they may all be one. As you, Father, are in me and I am in you, may they also be one in us, … so that the world may know that you have sent me.”278 The desire to recover the unity of all Christians is a gift of Christ and a call of the Holy Spirit. (2748)
Catholic Church. (2000). Catechism of the Catholic Church (2nd Ed., p. 217). Washington, DC: United States Catholic Conference.
Finally, He prays for all together; He asks for the entire Church, the gift of perfect union among themselves, similar to the union existing among the Persons of the Adorable Trinity, and the ineffable blessings of eternal happiness (21–26).
21. “That they all may be one.” He asks for all, for the entire Church, the same blessing of unity that He had already asked for the Apostles (v. 11). Here, He prays only for the faithful; elsewhere, as on the cross, He prays for His enemies and unbelievers (v. 9–11). “All one,” united in the bonds of faith, hope, charity concord and subordination, in a manner similar, though unequal, to the essential union of the Divine nature. The union of will and love which exists in us, “as Thou, Father, in Me,” and that this perfect union may be forwarded and accomplished by their union with us in sanctifying grace, and supernatural love of charity, which makes us, as it were, partakers of the Divine nature.
“May be one in us, as Thou,” etc. “As,” can only convey a similarity of union in some respects; but, not equality. For creatures could never attain the adorable union that exists in the Godhead. The three Persons in the Godhead are united by the same Divine nature, identical in each. We are united in an analogous or similar way, by concord and charity and subordination, which has its origin and binding power and persevering stability in God’s grace, “one in us,” and this union our Lord here prays for all the members of His Church.
“That the world,” all mankind, believers and unbelievers, “may believe;” the believers confirmed in their faith; and the unbelievers brought to embrace it, on beholding this moral miracle of supernatural union, which could come from God alone, between the faithful among themselves, as well as their union with God. “That Thou hast sent Me,” and, that My doctrine comes from Thee which was the great theme of His own preaching and that of the Apostles.
MacEvilly, J. (1902). An Exposition of the Gospel of St. John (pp. 322–323). Dublin: M. H. Gill & Son.
