The liturgy is the prayer of the Church. As such, it is a most important means by which many graces are obtained for the benefit of the Church. Liturgy is thus a force which forms and preserves the Church in her spiritual life. The liturgy makes the Church, builds her up, fortifies her. But is there not a sense in which the converse is also true? Does not the Church make the liturgy?
I answer that both statements are true, but with some necessary distinctions. When I say that the liturgy makes the Church, I mean that it forms her members in holiness and helps them on their way to salvation. When I say that the Church makes the liturgy, I am alluding to the fact that anything which contributes to salvation belongs to the Church. Hence, the Church makes the liturgy for exactly the same purpose that the liturgy makes the Church: to save her members. So obviously I am using “Church” and “make” differently here.
To delve more deeply: when I say that the Church makes the liturgy, I am not speaking of the members of the Church who are in need of saving so much as of the Mystical Body of Christ from which, like blood and water, pour fourth all the graces and aids necessary for salvation. In a sense, yes, this Mystical Body is composed of the members of the Church; and yet it would be strange, even heterodox (as far as I can tell), to say that the members of the Church can determine for themselves what will best contribute to their sanctification and salvation. So the Church cannot make the liturgy in the sense of her members making the liturgy. It is in a very different, more mystical sense, that the Church makes the liturgy. The liturgy can only be the product of the Church to the extent that it is the work of God’s hands, and not to the extent that it is the “work of human hands.”
But when I say that the liturgy makes the Church, then I am using “Church” to refer more directly to her members. And the reason for this is already evident: because the liturgy is a means by which the graces necessary for salvation are communicated to man. The liturgy is a means of grace because it is prayer – indeed, in a sense, the highest form of prayer, being the prayer of the universal Church. This is not to downgrade the importance of private contemplative prayer; but in a sense, contemplative prayer reaches its greatest heights in the context of the liturgy itself. Accordingly, the Christian man grows in grace, in faith, hope, and charity, and in sanctity. The liturgy has made him holy.
Thus, we have seen how it is possible to say both that the Church makes the liturgy, and the liturgy makes the Church. Once again, I emphasize how these principles entail the very great importance of tradition in the liturgy. Man has a part in the development of the liturgy only insofar as he is the instrument through which God makes the liturgy. As such, man may not act primarily as the arbiter of the liturgy; rather, he is spiritually and morally bound to act primarily as the receiver of the liturgy. His role is primarily passive, just as a tool is passive in the hands of the Carpenter. Man may not form the liturgy according to his own desires and personal fancies; rather he must form the liturgy according to what he has received, just as the tool shapes a table according to the pattern imposed upon it by the mind of the Carpenter. Thus, liturgical tradition in the Catholic Church, even if merely a “disciplinary” tradition, is in a very real sense divine – not, indeed, in the sense in which dogma originates from the lips of the Redeemer or the inspiration of the Holy Spirit (divine revelation), but in the sense that it is the sure manifestation of the Will of Divine Providence for the Church in every age of history.
These principles give us reason to question whether a liturgy formed by a commission or even a Pope is therefore legitimately formed by the Church. Certainly a commission or a Pope can legitimately form the liturgy according to tradition, but if either of these becomes the sole arbiter of the liturgy, disregarding liturgical tradition, then it seems that this would not be legitimate. This would follow even if the liturgy produced in such a circumstance were not in any way contrary to divine revelation, for it would still be the product of a rebellion against Divine Providence as it manifests itself in tradition governing the Church. In one sense, such a liturgy is produced by the Church insofar as it is by those members of the Church who hold ecclesiastical authority - and indeed, these are endowed with a true authority. Nonetheless, that authority is given for the sake of the spiritual welfare of the faithful, which is best determined by tradition; hence, while an abuse of that authority might technically be an act of the Church, it is contrary to the spirit by which the Church ought to regulate her actions.
We might make a further clarification by way of analogy: the body and soul of the Church. The former refers to the external and visible side of the Church, the latter to the spirit which ought to animate her external regulations. A liturgy of the sort I have just described would indeed be from the Church as from her body, but would not be fully conformed to her soul: much in the same way that a body that is afflicted with some illness is somehow at variance with its nature, its soul. The Church, of course, being indefectible, can never be at so great a variance with her soul as to be destroyed (death=separation of body and soul); the Church is protected by the Holy Spirit from ever actually opposing the heart and essence of the faith itself, and will always be efficacious towards salvation. But this efficacy is at its best and greatest when tradition is obeyed. Tradition is the sign of a healthy Church.
In summary, when it comes to spiritual matters, even if they are "disciplinary," tradition is the surest medium through which God communicates His Will to the Church. Tradition is the expression of the very soul of the Church; it is the guardian and preserver of the spiritual well-being of the Church. This applies preeminently to the sacred liturgy, which is undoubtedly a spiritual discipline of the highest value and dignity. The liturgy is one of the most important means by which the Church is nourished spiritually. Hence it is of the greatest importance that tradition be preserved in the liturgy.