The priesthood of Christ is precisely the contradiction of alienation. By the gift of Himself in obedience to the Will of the Father, the Second Person of the Trinity, subdued His human will and obeyed with it. In the flesh, He lived out who He was as Divine Person. Note that Christ obeyed with His human will. In Jn 5. 38, we read: “I have come down from heaven not to do my (own) will, but the Will of Him Who sent Me. Cardinal Ratzinger remarks:
“The Council of Constantinople (680-681 Maximus the Confessor: Protagonist) has analyzed concretely the problem of the two natures and one person in Christ in view of the problem of the will of Jesus. We are reminded firmly that there exists a specific will of the man Jesus that is not absorbed into the divine will. But this human will follows the divine will and thus becomes a single will with it, not, however, in a forced way but by way of freedom. The metaphysical duplicity of a human will and a divine will is not eliminated, but in the personal sphere, the area of freedom, there is accomplished a fusion of the two, so that this becomes not one single natural will but one personal will. This free union – a mode of union created by love – is a union higher and more intimate than a purely natural union. It corresponds to the highest union which can exist, the union of the Trinity
The Council explains this union by saying of the Lord given in the Gospel of John ‘I have come down from heaven, not to do my own will, but the will of him who sent me’ (John 6, 38), Here the divine Logos is speaking of the human will of Jesus in the mode by which he calls his will the will of the Logos. With this exegesis of John 6, 38, the Council proves the unity of the subject. In Jesus there are not two ‘I’s,’ but only one. The Logos speaks of the will and human thought of Jesus using the ‘I.’; This has become his ‘I,’ has been assumed into his ‘I,’ because the human will has become fully one with will of the Logos, and with it has become pure assent to the will of the Father.”
Let me say this perhaps more clearly and simply. There is a metaphysical principle in St. Thomas whereby he says that “actions sunt suppositorum.” That is, free actions are only performed by subjects. That is, objects act according to nature by way of necessity, but not “freely.” Free actions presuppose knowledge and the power to self-determine. Or, better, only subjects or persons can determine themselves. It all comes down to the Council of Chalcedon (451) that taught that there is only one person (1) in Christ, the divine Person, Son of the Father, and two natures, divine and human. The Council of Constantinople III (671-671) explains that the human (created) will of Jesus is exercised by the one divine Person. The uncreated Son – the divine Person – does not will with the uncreated divine Will, but with the created human will. And since that human created will “became sin,” the Divine Person of the Son destroys sin (which is the contradiction of the divine Person Who is pure gift and relation to the Father). Hence, the Redemption. Human nature is turned about away from self.
Thus the “priesthood” of Jesus Christ. This is Who He is. And who we are when baptized and ordained into Him. And the spirit of Opus Dei is the confluence of the two sacramental manifestations of this one priesthood of Jesus Christ. And this why the Catholic Church is a “priestly people.” This was the development that took place in Vatican II. The Church ceased to be understood in terms of hierarchy, i.e. the ordained ministerial priesthood as its supreme power centered in the papacy, but the baptized faithful called to live out the priesthood of Christ in ordinary, secular life. And the ordained ministerial priest is now understood to be at the service of the “common” priesthood of the faithful laity or religious.
Vatican II was the re-thinking of the Church in these terms as can be seen in Lumen Gentium #10:
“10. Christ the Lord, High Priest taken from among men,(100) made the new people “a kingdom and priests to God the Father”.(101) The baptized, by regeneration and the anointing of the Holy Spirit, are consecrated as a spiritual house and a holy priesthood, in order that through all those works which are those of the Christian man they may offer spiritual sacrifices and proclaim the power of Him who has called them out of darkness into His marvelous light.(102) Therefore all the disciples of Christ, persevering in prayer and praising God,(103) should present themselves as a living sacrifice, holy and pleasing to God.(104) Everywhere on earth they must bear witness to Christ and give an answer to those who seek an account of that hope of eternal life which is in them.(105)
Though they differ from one another in essence and not only in degree, the common priesthood of the faithful and the ministerial or hierarchical priesthood are nonetheless interrelated: each of them in its own special way is a participation in the one priesthood of Christ.(2*) The ministerial priest, by the sacred power he enjoys, teaches and rules the priestly people; acting in the person of Christ, he makes present the Eucharistic sacrifice, and offers it to God in the name of all the people. But the faithful, in virtue of their royal priesthood, join in the offering of the Eucharist.(3*) They likewise exercise that priesthood in receiving the sacraments, in prayer and thanksgiving, in the witness of a holy life, and by self-denial and active charity.”
The relation of the two sharings in the one Priesthood of Jesus Christ: Footnote 55 of “Dignity and Vocation of Women” John Paul II:  “This Marian profile (Our Lady who is not ordained minister but sacramentaly equivalent to the baptized layman) is also–even perhaps more so–fundamental and characteristic for the Church as is the apostolic and Petrine profile to which it is profoundly united. …The Marian dimension of the Church is antecedent to that of the Petrine, without being in any way divided from it or being less complementary. Mary Immaculate precedes all others, including obviously Peter himself and the Apostles. This is so, not only because Peter and the Apostles, being born of the human race under the burden of sin, form part of the Church which is ‘holy from out of sinners,’ but also because their triple function has no other purpose except to form the Church in line with the ideal of sanctity already programmed and prefigured in Mary. A contemporary theologian has rightly stated that Mary is ‘Queen of the Apostles without any pretensions to apostolic powers: she has other and greater powers’ (H. U. von Balthasar, “Neue Klarstellungen“).” Address to the Cardinal and Prelates of the Roman Curia (December 22, 1987); “L’Osservatore Romano,” December 23, 1987.
This has been the impact of the ordination of St. Josemaria Escriva: The Church as “People of God” (and therefore a “Communio” where one becomes who one is only in relation to another) and de-centralized from the clerical “elite” who have hitherto been identified as the Church itself and now understood to be in the service of all.
 J. Ratzinger, “Journey to Easter,” Crossroad (1987) 101-102.
 “He made Him to be sin who knew nothing of sin” (2 Cor. 5, 28).