Before considering the form of the Consecration, it is important to consider the Catholic teaching about Sacraments. This explanation is taken from the Apostolic Constitution on Sacred Orders (Sacramentum Ordinis) by Pope Pius XII. “It is evident to all that the Sacraments of the New Law in so far as they are perceptible and efficient signs of invisible grace, should signify the grace they produce and produce the grace they signify. Indeed, the effects which must be produced and therefore signified by the sacred ordination of deaconate, priesthood, and episcopate (namely, power and grace) [sic] are found sufficiently signified in all rites of the universal Church, of different periods and places, by the imposition of hands and the words determining it.” [bold and underlined emphasis added; italics and parentheses in original]
Pope Pius XII declared ex cathedra in this document that “the matter of the Sacred Orders of deaconate, priesthood, and the episcopate is the imposition of hands. The form is the words determining the application of the matter, by which the sacramental effects are univocally signified --- namely the power of Orders and the grace of the Holy Spirit.” [italics are in the original but bold and underlined are added here for emphasis]
In other words the words of the form must specify what power of orders is given and that the grace of the Holy Ghost is given. Therefore in this ceremony the “grace and power of the episcopacy must be signified and conferred.” Catholic Encyclopedia,
Vol. IV, p. 278, Consecration, 1913 ed. Pope Pius XII states that for the episcopacy, the words of the Preface are the form and the essential words of this form for validity are: “Comple in Sacerdote tuo ministerii tui summam, et ornamentis totius glorificationis instructum coelestis unguente rore sanctifica.” This translated is: “Fill up (complete, perfect) in Thy Priest the perfection (sum total) of thy ministry and sanctify with the dew of
Thy heavenly ointment this Thy Servant (the Bishop-elect) decked out (adorned, embellished) with the ornaments of all beauty (glory).”
By saying essential words, Pope Pius XII is saying this is an example of the bare minimum needed for validity. Furthermore, Pope Pius XII states, “It shall be in no way right to understand from what we have declared and ordained above as
to matter and form, that it would be lawful to neglect in any way or to omit the other established rites of the Roman Pontifical.
Indeed, We ever command that all the prescribed details of that Roman Pontifical be religiously observed and carried out.”
With all of the above in mind, a better and more proper comparison can be made between the Old and New forms of Episcopal Consecration.
CONCLUSION.
The modern rite of consecration and the new mass are fruits of the post-Vatican II revolution. Our Lord advised us to make judgments when he said, “By their fruits you shall know them. . . . Even so every good tree bringeth forth good fruit, and the evil tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can an evil tree bring forth good fruit.” (St. Matthew 7:16, 18). Indeed, the above comparisons are meant to inform Catholics about the exact changes made in this rite so they can make an educated judgment about the new rite. The reader, thus, can draw his own conclusions about the changes and this fruit of the revolution.