No Mass is "Private"

32. It is also only fitting for us to recall the conclusion that can be drawn from this about "the public and social nature of each and every Mass." ²⁸ For each and every Mass is not something private, even if a priest celebrates it privately; instead, it is an act of Christ and of the Church. In offering this sacrifice, the Church learns to offer herself as a sacrifice for all and she applies the unique and infinite redemptive power of the sacrifice of the Cross to the salvation of the whole world. For every Mass that is celebrated is being offered not just for the salvation of certain people, but also for the salvation of the whole world. The conclusion from this is that even though active participation by many faithful is of its very nature particularly fitting when Mass is celebrated, still there is no reason to criticize but rather only to approve a Mass that a priest celebrates privately for a good reason in accordance with the regulations and legitimate traditions of the Church, even when only a server to make the responses is present. For such a Mass brings a rich and abundant treasure of special graces to help the priest himself, the faithful, the whole Church and the whole world toward salvation—and this same abundance of graces is not gained through mere reception of Holy Communion.

33. And so, We recommend from a paternal and solicitous heart that priests, who constitute Our greatest joy and Our crown in the Lord, be mindful of the power they have received from the bishop who ordained them—the power of offering sacrifice to God and of celebrating Mass for the living and for the dead in the name of the Lord. ²⁹ We recommend that they celebrate Mass daily in a worthy and devout fashion, so that they themselves and the rest of the faithful may enjoy the benefits that flow in such abundance from the Sacrifice of the Cross. In doing so, they will also be making a great contribution toward the salvation of mankind.