According to Pius XII’s encyclical Mediator Dei, the sacrifice of the Mass is offered by the fact that the priest makes the body and blood of Jesus to be present on the altar (see paragraph 92). Despite everything we can say about a “priesthood of all the faithful,” only an ordained priest can turn bread and wine into the body and blood of Jesus. But Pius XII is equally insistent that all of us in the pews really do offer the sacrifice of the Mass. How does that work?Let’s compare the Mass with something outwardly similar. Suppose that a bunch of Catholics gathered in a church to watch Stan the carpenter build a table in the sanctuary. Suppose that the faithful wholeheartedly supported Stan’s project, and they even voiced their support with acclamations and songs and upraised hands. Now let me ask you: when the project is done, would we say that the faithful built the table? Wouldn’t we actually say that Stan the carpenter built the table while the faithful watched?
On the surface, a Mass seems pretty similar. The faithful gather in a church, and they watch a priest recite the words of consecration by which the Eucharistic sacrifice is made present. Ideally, they support the priest, and they express their support by making responses at the appropriate times and by singing songs, and they stand and kneel and do the other gestures called for in the Mass. So what are the differences between building a table and offering a Mass?
When you think about it, celebrating Mass and building a table each consist of three elements: (1) a person (2) does something (3) to some object. For each of these three elements, we can see a difference between the two situations:
- The person doing the action is different. Stan the carpenter is just Stan, a carpenter, but the priest acts as an instrument of Christ, the head of the Church. This means that the priest has a relation to the people that a carpenter wouldn’t have, namely he acts as the head of which they are the mystical body. Anything he does, they have a part in, and all the more as they consciously intend to have a part.
- The object of the action is different. The carpenter builds a table, nothing more, but when Christ offers his body in the Mass he offers his entire body, including the members. Really, the faithful themselves are included in the object of the action as members of the victim. If you think about it, Christ’s offering of his members can’t be complete unless those members consent to it—a table you can consecrate just by blessing it, but people only become holy by wanting it interiorly.
- The action itself is different in kind. The building of a table is your everyday physical action, like tying a shoe. It just is, no matter what it looks like. But the performance of a sacrament is the making of a sign, and so what it looks like is part of the doing of it. The physical, visible presence of the people in the church building signifies their relation to the priest and to what he is doing, and so their physical, visible presence in the church building is actually bound up with the kind of action he is doing. They take part in the action by their visible presence: attending Mass is part of the sacramental sign. This is why, for example, Catholics can’t fulfil their Sunday Mass obligation by spiritually uniting their intentions with the Mass from home.
And there you have the three ways laypeople truly offer the Mass: by the hands of the priest, who represents their head; by uniting their intentions with Christ’s in offering the entire body of Christ; and by their significant physical presence.