For centuries, going back into the mists of time, the priest has said the words “Mysterium fidei” in the midst of the words of consecration whispered over the chalice. These words powerfully evoke the irruption or inbreaking of God into our midst in this unfathomable Sacrament. The consecration of the wine completes the signification of the sacrifice of the Cross, the moment when our High Priest obtained for us eternal redemption (cf. Heb 9:12), the re-presentation of which, together with the application of its fruits, is the very purpose of the Mass.and
Even if the words mysterium fidei are not necessary for signifying transubstantiation (and thus, the consecration can be “effective,” and the Mass “valid,” without them), the removal of the phrase from its age-old position exudes the attitude: nothing is sacred.Does this use of "mysterium fidei" match what St. Paul means by the Mystery, Christ becoming Incarnate so that we may be incorporated in Him? If that is what St. Paul meant, then why would "mysterium fidei" be used before anyone had actually received Holy Communion?