The local community is dependent on the bishop, a person whose office is rooted in the Church’s apostolicity, to provide a “president” for the celebration of the Eucharist.
29. The expression repeatedly employed by the Second Vatican Council, according to which “the ministerial priest, acting in the person of Christ, brings about the Eucharistic Sacrifice”, (Cf. Lumen Gentium 10 and 28; Presbyterorum Ordinis 2.) was already firmly rooted in papal teaching. (“The minister of the altar acts in the person of Christ inasmuch as he is head, making an offering in the name of all the members”: Pius XII, Encyclical Letter Mediator Dei (20 November 1947): AAS 39 (1947), 556; cf. Pius X, Apostolic Exhortation Haerent Animo (4 August 1908): Acta Pii X, IV, 16; Pius XI, Encyclical Letter Ad Catholici Sacerdotii (20 December 1935): AAS 28 (1936), 20.) As I have pointed out on other occasions, the phrase in persona Christi “means more than offering ‘in the name of’ or ‘in the place of’ Christ. In persona means in specific sacramental identification with the eternal High Priest who is the author and principal subject of this sacrifice of his, a sacrifice in which, in truth, nobody can take his place”. (Apostolic Letter Dominicae Cenae (24 February 1980), 8: AAS 72 (1980), 128-129.) The ministry of priests who have received the sacrament of Holy Orders, in the economy of salvation chosen by Christ, makes clear that the Eucharist which they celebrate is a gift which radically transcends the power of the assembly and is in any event essential for validly linking the Eucharistic consecration to the sacrifice of the Cross and to the Last Supper. The assembly gathered together for the celebration of the Eucharist, if it is to be a truly Eucharistic assembly, absolutely requires the presence of an ordained priest as its president. On the other hand, the community is by itself incapable of providing an ordained minister. This minister is a gift which the assembly receives through episcopal succession going back to the Apostles. It is the Bishop who, through the Sacrament of Holy Orders, makes a new presbyter by conferring upon him the power to consecrate the Eucharist. Consequently, “the Eucharistic mystery cannot be celebrated in any community except by an ordained priest, as the Fourth Lateran Council expressly taught”. (Congregation for the Doctrine of the Faith, Letter Sacerdotium Ministeriale (6 August 1983), III.4: AAS 75 (1983), 1006; cf. Fourth Lateran Ecumenical Council, Chapter 1, Constitution on the Catholic Faith Firmiter Credimus: DS 802.)
By way of tradition, Pope John Paul reaffirms traditional Roman teaching about the principle of no priest/no Eucharist.