Western Christianity has always used the Institution narrative as its form of eucharistic consecration. “This is my body” and “this is my blood” (perhaps with “given up for you” added) certainly do signify the substance of the sacrament…the bread and wine become the body and blood of Christ (some argue that the reference to being “given up” for us is needed too…because part of the substance of the sacrament is its nature as a sacrafice too) And if the priest intends to consecrate at this moment, it certainly is sufficient.
However, there has been great debate with the East over the nature of the Epiklesis. In Western Christianity it is definitely NOT the words of consecration. We phrase it in the subjunctive (ie, send your spirit upon these gifts so that they “may” become the body and blood of Christ) But in the East, they often consider the epiklesis the words of consecration…and yet it comes after the institution narrative. Nevertheless, if they do not intend to consecrate at the institution narrative…their Epiklesis certainly does seem more than adequate for expressing the essence of the sacrament:
we offer to You this spiritual and unbloody sacrifice, and we implore and pray, and entreat You, send down Your Holy Spirit upon us and upon these gifts here present. (Blessing the bread) And make this bread the precious body of Your Christ. (Blessing the chalice) And that which is in this chalice, the precious blood of your Christ. (Blessing both) Having changed them by Your Holy Spirit
I would say certainly that conveys the essence of the sacrament very well! In the Eastern Rites of the Catholic Church, especially during periods of latinization, the priests were often told by Rome to intend the moment of consecration to be the institution narrative. And yet the tradition of intending the consecration at the epiklesis, as the orthodox do and as is the tradition for eastern catholics, is being more accepted as valid because clearly their epiklesis conveys the whole substance of the sacrament (bread and wine becoming the body and blood of Christ as an unbloody re-presentation of Jesus’s sacrafice) especially since it is in the present imperative (make this bread…) and not a future subjunctive like in the latin rite (ie, so that it “may”)…
Rome even recently approved Chaldean Catholics to recieve communion in the Assyrian Church of the East in cases of necessity, even though the Assyrians often use an anaphora (“of Addai and Mari”) that contains
no institution narrative. Though Rome does request that the Assyrians add the institution narrative just to be safe and to conform to the almost otherwise universal tradition of including it…she has said that the eucharist is probably still valid and Catholics may recieve it in cases of necessity because the liturgy of Addai and Mari does contain statements like this:
Do Thou, O Lord, through Thy many and ineffable mercies, make the memorial good and acceptable with that of all the pious and righteous fathers who have been pleading before Thee in the commemoration of the body and blood of Thy Christ, which we offer to Thee upon Thy pure and holy altar, as Thou hast taught us; and grant unto us Thy rest all the days of this life.
And may Thy Holy Spirit come, O Lord, and rest upon this oblation of Thy servants which they offer, and bless and sanctify it;
Which do seem to adequately convey the substance of the sacrament, yet without being, strictly speaking, an institution narrative. Yet I think they certainly convey the substance of the sacrament, namely the offering of the body and blood of Christ as a re-presentation of the sacrafice of calvary.
The Church is moving away from the “magic words” attitude where a specific set formula is needed absolutely. Rather, the form simply must convey the substance of the sacrament…whether this be in the institution narrative, the epiklesis, or equivalent prayers from the the liturgy of addai and mari. If the Form of confirmation can have as widely diverse forms as “be signed with the sign of the cross, and be confirmed with the chrism of salvation” and “be sealed as the gift of the holy spirit”…different Forms for the eucharist, as long as they all convey the essence of the mystery, can probably still be valid.
