Mediator Dei and Sacrosanctum Concilium

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Note: The opinions expressed in this article do not necessarily reflect the opinions of Clarifying Catholicism, nor of everyone affiliated with Clarifying Catholicism.

By Birdie Kopacz, Benedictine College

Mediator Dei and Sacrosanctum Concilium are both important Catholic works from the mid-20th century. They covered many important and relative topics of the time, and in a lot of ways these topics were similar. However, while there are many similarities in these documents, they approach the topics differently. Both of these works are focused on the liturgy, and they have some of the same ideas and some different ones. One of the biggest differences can be seen in the attitudes of a priest’s role in the Mass versus the faithful. Mediator Dei describes the priest as “the ambassador to the Divine Redeemer” (p. 11, pp. 40), and of having higher importance to the liturgy than the lay faithful. Sacrosanctum Concilium still acknowledges this importance but also stresses that the priest must encourage the “full and active participation of the faithful” (p. 3, pp.14) and seems to say that the faithful are equally as important to the liturgy as the priest is.

The first thing both of these works stress is how the liturgy is the priestly work of Christ on earth. Mediator Dei says “the divine Redeemer has so willed it that the priestly life begun with the supplication and sacrifice of His mortal body should continue without intermission down the ages in His Mystical Body which is the Church” (p. 1, pp. 2). Sacrosanctum Concilium, of course, agrees with this truth which is the central mystery of our faith. “Rightly, then, the liturgy is considered as an exercise of the priestly office of Jesus Christ” (p. 2, pp. 7). The central reason for the Mass is to offer this sacrifice, again and again. Christ Himself established the liturgy in his ministry, at the Last Supper, and in His sacrifice and Resurrection, and it is continuously renewed for us at Mass. He is the victim and He is the priest.

So of course it follows that both of these works acknowledge the importance of the earthly priest himself in the liturgy. One of the biggest points of Mediator Dei is to establish that the priest himself is Mediator Dei on earth. Sacrosanctum Concilium, even in its desire for the participation of the lay faithful, stresses the importance of the priest’s role in guiding them.

Yet it would be futile to entertain any hopes of realizing this unless the pastors themselves, in the first place, become thoroughly imbued with the spirit and power of the liturgy, and undertake to give instruction about it. A prime need, therefore, is that attention be directed, first of all, to the liturgical instruction of the clergy.

(p. 3, pp. 14)

Both documents recognize the necessity of the priest. He acts in persona Christi, He brings Christ to the faithful, so whether or not one would think the faithful are equally vital to the liturgy, one should not be able to find an excuse in either of these works to say that the priest is not vital. Even if one is harder to interpret than the other, the idea that priests are unnecessary is simply not there.

While Mediator Dei and Sacrosanctum Concilium agree on these extremely important points, the role of priest differs in each. Mediator Dei makes many points about the priest being of higher importance than the faithful. In paragraph 41, Pope Pius XII writes that “the visible, external priesthood of Jesus Christ is not handed down indiscriminately to all members of the Church in general, but is conferred on designated men, through what may be called the spiritual generation of holy orders” because the priesthood was only handed down to the apostles. In the sacrament of Holy Orders, priests are given an indelible character. This sets them apart from the lay faithful. It aligns the man with the priesthood of Christ, so that he can bring Christ to the people. This is something that the faithful cannot do for themselves, not to the fullness that the priest can.

Following this point, it is stated that the liturgy can only be left up to Church authority. It is stated in paragraph 44 this way: “Since, therefore, it is the priest chiefly who performs the sacred liturgy in the name of the Church, its organization, regulation and details cannot but be subject to Church authority. This conclusion, based on the nature of Christian worship itself, is further confirmed by the testimony of history.” This makes it clear that control of the liturgical rite cannot and should not be left up to the faithful. Pope Pius XII goes on to say that this is because:

The sacred liturgy is intimately bound up with doctrinal propositions which the Church proposes to be perfectly true and certain, and must as a consequence conform to the decrees respecting Catholic faith issued by the supreme teaching authority of the Church with a view to safeguarding the integrity of the religion revealed by God.

(Mediator Dei, p. 12, pp.45)

The rites of the liturgy are in custody, so to speak, of Church authority. This includes the Magisterium, all bishops, and all priests. The lay faithful do not have the indelible mark of the priesthood, we are the followers of doctrine. Therefore, we cannot determine the course the liturgy takes.

Sacrosanctum Concilium takes a seemingly different point of view on the subject. It is difficult to tell, due to the rather ambiguous language, but there is a large emphasis on the participation of the lay faithful. Paragraph 48 starts out stating this desire for lay participation in a way that doesn’t diminish the necessity for the priest.

The Church, therefore, earnestly desires that Christ’s faithful, when present at this mystery of faith, should not be there as strangers or silent spectators; on the contrary, through a good understanding of the rites and prayers they should take part in the sacred action conscious of what they are doing, with devotion and full collaboration.

(Sacrosanctum Concilium, p. 6, pp.48)

This is a good statement on its own, because, for their own good, the lay faithful should be participating in the sacraments. They are here to give us grace on earth. However, in various parts of the document, it puts the participation of the lay faithful on the same level as the participation of the priest. The entirety of paragraph 11 is a good example of not only this prioritization of lay participation, but also the ambiguity of the document.

But in order that the liturgy may be able to produce its full effects, it is necessary that the faithful come to it with proper dispositions, that their minds should be attuned to their voices, and that they should cooperate with divine grace lest they receive it in vain [28] . Pastors of souls must therefore realize that, when the liturgy is celebrated, something more is required than the mere observation of the laws governing valid and licit celebration; it is their duty also to ensure that the faithful take part fully aware of what they are doing, actively engaged in the rite, and enriched by its effects.

(Sacrosanctum Concilium, p. 2, pp. 11)

This paragraph makes it sound like without lay participation, the liturgy doesn’t come into fullness. Obviously this contrasts with Mediator Dei’s ideas about the priest being the most important human aspect of the Mass, as the one who offers the sacrifice of the Eucharist, but it also is incorrect in general. A sacrifice only needs a priest and a victim to be effective. In order for the sacrifice of the Eucharist to be offered in completion, the priest is the only one who has to receive communion. If participation of the laity was a deciding factor in the fullness of the liturgy, then the laity would be able to receive the graces of the sacrament regardless of the state of their soul. This could lead to a slippery slope of the state of grace in the soul not being important, thereby making the sacrament of Reconciliation not important. However, this is not the case. Catholics are discouraged from receiving communion if they’re in a state of mortal sin. The Church wouldn’t discourage reception of communion if laity participation wasn’t vital to the effectiveness of the liturgy itself.

Now, one could quite easily say that, when they speak of the liturgy being able to produce its full effects, they mean that the laity must participate to receive the full effects of the liturgy. That this is still speaking of participation for the sake of the laity rather than the sake of the liturgy. However, this speaks to a larger problem in the document itself. The language in this document is quite unclear. At best, it looks like this paragraph could go either way and it seems to have been applied in the way described in the initial analysis–that the liturgy needs the lay faithful, rather than the lay faithful needing the liturgy alone.

The implication that the laity must participate for the liturgy’s sake is also made in paragraph 50: “The rite of the Mass is to be revised in such a way that the intrinsic nature and purpose of its several parts, as also the connection between them, may be more clearly manifested, and that devout and active participation by the faithful may be more easily achieved.” Again, the wording is tricky, but it sounds like they’re saying the clear manifestation of the liturgy has dependency on that participation of the laity. Regardless, this once again speaks to the problem of ambiguity in this document, because even if the intentions and meanings are all correct in the context of Church teaching, it can easily lead to much misinterpretation.

Both Mediator Dei and Sacrosanctum Concilium are important writings in the Church. They have both been extremely influential in the directions the Church has taken with the liturgy. However, even though they deal with very similar topics, and agree on important subjects, they disagree on a very important aspect, which is the prioritizing of the participation of priests versus the prioritizing of the participation of the faithful. Mediator Dei clearly puts the participation of the priest at the highest priority, and that the faithful should participate for the sake of their own souls. Sacrosanctum Concilium is not nearly as clear, but still presents the idea that the faithful must participate in the liturgy, not only for the sake of their own souls, but for the sake of the liturgy itself. Whether or not that was the intention, the ambiguity of the document has led to this interpretation and this can be seen in the Church today. This disagreement in Church writings, happening within a 20-year timeframe, gives much food for thought when one is looking at the intense diversity of Church liturgy now.

Works Cited

Pope Pius XII. “Mediator Dei.” The Holy See, 20 Nov. 1947,

Second Vatican Council, Constitution on the Sacred Liturgy Sacrosanctum concilium (4 December 1963),

Edited by: GraceAnne Sullivan

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