Here we would like to cite Jean Borella, whose work on this subject is indispensable:
[J]ust as the whole Christic deed, all the acts accomplished by Jesus of Nazareth on this earth, is summarized and founded in the ultimate act of his redemptive Passion, so all rites and all sacraments, by which the permanent actuality of the Christic deed is assured until the end of the world, are summarized and founded in the ultimate rite of the sacrificial Memorial of the Passion. In short, this signifies that Christianity is identified with the ritual action of the Divine Liturgy. From this point of view, that of its formal specificity, it is perfectly just to say, with Dom Casel, that Christianity is a mystery religion by essence, since Mystery can be defined as That which, in the Divine Work (the Mystery of salvation) comes to inform and configure human action so that it becomes a sacramental anamnesis, forming in this way an initiatic community separated from the world of profane action. And, in fact, the participation of the faithful in this ritual configuration in act truly and very really initiates them into the very Life of God and sacramentally unites them with his redemptive action. This is why the mention of ‘Mysterium fidei’, inserted by the Church at a very early date into the scriptural formula of Eucharistic consecration, should be understood only in the sense of the miracle of transubstantiation to which faith alone enables us to gain access.
We will develop this thought when we come to the section dedicated to the divine liturgy.