Two council documents, on the Church, and on the ministry and life of priests, are quoted to start off:
With regard to presbyters, the following should be recalled from acts of the Second Vatican Council: “Although presbyters do not possess the highest degree of pontificate and although they are dependent upon the bishops in the exercise of their power, they are nevertheless united with the bishops in priestly dignity; and in virtue of the sacrament of orders they are consecrated in the image of Christ the eternal high priest (see Hebrews 5: 1-10; 7:24; 9: 11-28) as true priests of the New Testament to preach the Gospel, shepherd the faithful, and celebrate the worship of God.”(Lumen Gentium 28) In another place the Council says: “By sacred ordination and by the mission they receive from the bishops, presbyters are promoted to the service of Christ the Teacher, the Priest, and the King. They share in his ministry of unceasingly building up the Church on earth into the people of God, the body of Christ, and the temple of the Holy Spirit.” (Presbyterorum Ordinis 1) In the ordination of presbyters, as found in the Roman Pontifical, the mission and grace of the presbyter as a helper of the episcopal order have been very clearly described. Yet it seemed necessary to restore the entire rite, which had been divided into several parts, to greater unity and to express in sharper light the central part of the ordination, that is, laying on of hands and the consecratory prayer.
Paul VI gives the reasons why the rite for ordaining presbyters was reformed: for greater unity, plus the desire to underscore the core aspects of laying on of hands and the prayer.
Finally, with regard to deacons, in addition to the content of our apostolic letter Sacrum Diaconatus Ordinem issued motu proprio on June 18, 1967, the following should be especially recalled: “In the lower grade of the hierarchy are deacons, on whom hands are laid ‘not for the priesthood, but for the ministry’ (Constitutions of the Church of Egypt, III, 2). Strengthened by sacramental grace, they serve the people of God in the diaconia of liturgy, word, and charity, in communion with the bishop and his presbyterium.” (Lumen Gentium 29) In the ordination of deacons a few changes had to be made to satisfy the recent prescriptions about the diaconate as a distinct and permanent grade of the hierarchy in the Latin Church or to achieve a greater simplicity and clarity in the rites.
The changes in diaconate ordination were also logical ones: to draw out the conciliar prescriptions about the order, in addition to the streamlining.
Among the other documents of the supreme magisterium pertaining to sacred orders, we consider one worthy of particular mention, namely, the apostolic constitution Sacramentum Ordinis published by our predecessor, Pius XII, on November 30, 1947. In this constitution he declared that “the sole matter of the sacred orders of diaconate and presbyterate is the laying on of hands; likewise the sole form is the words determining the application of this matter, which univocally signify the sacramental effects-namely, the power of orders and the grace of the Holy Spirit-and are accepted and used as such by the Church.” (Sacramentum Ordinis 6) After this, the document determines which laying on of hands and which words constitute the matter and form in the conferring of each order.
“Matter” and “form” are the classical necessities for valid sacramental celebration. Note the Church’s care in laying out these very clearly. Remember that liturgy is for the benefit of the faithful as intimated earlier in this document. We might conclude that the expression of valid ordination is more for the edification of the faithful rather than only as a guarantee for the ordinands.