“Once in Rome, he resumed conversations with members of the Roman Curia to expedite a juridical framework suitable for papal approval of the Work… (O)n the feast of the Immaculate Conception he was received in audience by Pope Pius XII. On the 16th he wrote again to those in Madrid: ‘Do not forget that it has been during the octave of the feast of the Immaculate Conception that the solution in Rome began to jell’…
“On February 2, 1947, Pope Pius XII gave his consent to the apostolic constitution Provida Mater Ecclesia. Thus a juridical framework was established within which it was possible to proceed to the pontifical approval of Opus Dei. On February 14 the ‘Congress’ of the Sacred Congregation for Religious… voted favorably on this proposal. The Roman Pontiff in an audience granted to Cardinal Lavitrano on February 24 ratified their opinion. Thus Opus Dei with the Priestly Society of the Holy Cross was approved as a Secular Institute of pontifical right together with its constitutions. The decision of Pius XII was formalized in the Decretum laudis, entitled Primum Institutum and dated February 24, 1947… Opus Dei was thus given its international charter. But he [Escriva] doesn’t hide the need to take further steps along the juridical path.”
That done, the way was now open for the Second Vatican Council (as will become evident in the Dogmatic Constitution Lumen Gentium - The People of God) that was an epistemological turn from object to subject to affirm the radical equality of both lay faithful and ministerial priests in the Church, all with an equal call to sanctity, and yet with essentially different ways of sharing in the one priesthood of Christ (LG #10). I offer the mind of D. Alvaro del Portillo on the common legal status of all the faithful [as “other Christs”] in the Church:
Vatican II (Lumen Gentium): The Key to the Radical Equality of All the Baptized:“The basis of this whole problem and the key to its solution lies in one incontrovertible fact, emphasized with unprecedented vigour by the Second Vatican Council, namely that all persons who belong to the Church have a common fundamental legal status, because they all share one and the same basic theological condition land belong to the same primary common category. All the faithful, from the Pope to the child who has just been baptized, share one and the same vocation, the same faith, the same faith, the same Spirit, the same grace. They are all in need of appropriate sacramental and spiritual aids; they must all live a full Christian life, following the same evangelical teachings; they must all lead a basic personal life of piety – that of children of God, brothers and disciples of Christ – which is obligatory for them before and above any specific distinction which may arise from their different functions within the Church. The all have an active and appropriate share – within the inevitable plurality of ministries – the single mission of Christ and of the Church. Therefore it follows logically that within the Church all members have certain fundamental rights and obligations in common.”
The Final Juridical Step: The Personal Prelature
The Final Step: The Prelature as guardian of 1) the oneness of the subjective vocation of both laity and priests forming a "communio": each, being sacramentally irreducible [by Baptism and Orders], makes the total gift of self being dynamized to do so by the pastoral charity (fatherhood) of the Prelate; and 2) secularity as “characteristic” whereby the world of work and family is the occasion of the self-giving.The Conciliar Decree Presbyterorum Ordinis #10 reads: “Where the nature of the apostolate demands this, not only the proper distribution of priests should be made easier but also the carrying out of special pastoral projects for the benefit of different social groups in any region or among any race in any part of the world. For this purpose there can with advantages be set up some international seminaries, special dioceses, or personal prelatures and other institutions to which, by methods to be decided for the individual undertaking and always without prejudice of the rights of the local ordinaries, priests can be attached or incardinated for the common good of the whole Church.”
On August 6, 1966, Paul VI wrote the Apostolic Letter Ecclesiae Sanctae for the implementation of, in our case, Presbyterorum Ordinins #10: It read:
“There is no reason why laymen, whether celibate or married, should not dedicate their professional service, through contracts with the prelature, to its works and enterprises.
“Such prelatures shall not be erected without first hearing the views of the episcopal conferences of the territory in which they will serve. In the exercise of their function care is to be shown that the rights of the local ordinaries are not infringed and that close relations are kept with the episcopal conferences at all times.”John Paul II erects Opus Dei as a personal prelature: November 28, 1982: Apostolic Constitution Ut Sit of universal extension.
 Rodriguez, Illanes… “The Canonical Path of Opus Dei” Four Courts Press (1994) 167-168.
 Alvaro del Portillo, “Faithful and Laity in the Church,” Ecclesia Press (Shannon, Ireland) (1972) 19.