The Mystery of Faith, that is, the ineffable gift of the Eucharist that the Catholic Church received from Christ, her Spouse, as a pledge of His immense love, is something that she has always devoutly guarded as her most precious treasure, and during the Second Vatican Council she professed her faith and veneration in a new and solemn declaration. (cf. Constitution on the Sacred Liturgy, 47)

. . the ministerial and hierarchical priesthood, the priesthood of the bishops and the priests, and, at their side, the ministry of the deacons—ministries which normally begin with the proclamation of the Gospel—are in the closest relationship with the Eucharist. The Eucharist is the principal and central raison d’etre of the sacrament of the priesthood, which effectively came into being at the moment of the institution of the Eucharist, and together with it. Not without reason the words “Do this in memory of me".

The Church draws her life from the Eucharist. This truth does not simply express a daily experience of faith, baut recapitulates the heart of the mystery of the Church.