Vol. XVIII, No. 2
57. (1) Concelebration whereby the unity of the priesthood is appropriately manifested has remained in use to this day in the Church both in the East and in the West. For this reason it has seemed good to the Council to extend permission for celebration to the following cases:
1. (a) On the Thursday of the Lord’s Supper, not only at the Mass of the Chrism, but also at the evening Mass.
(b) At Masses during Councils, Bishops’ Conferences and Synods.
(c) At the Mass for the Blessing of an abbot.
2. Also, with permission of the Ordinary, to whom it belongs to decide whether concelebration is opportune:
(a) at conventual Mass, and at the principal Mass in churches, when the needs of the faithful do not require that all the priests available should celebrate individually;
(b) at Mass celebrated at any kind of priests’ meetings whether the priests be secular or religious.
(2) 1. The regulation, however, of the discipline of concelebration in the diocese pertains to the bishop.
2. Each priest shall always retain his right to celebrate Mass individually, though not at the same time in the same church as a concelebrated Mass nor on the Thursday of the Lord’s Supper.
58. A new rite for concelebration is to be drawn up and inserted into the Pontifical and into the Roman Missal.
(Pope Benedict’s post-Synod apostolic letter, February 22, 2007)
61. The Synod considered the quality of participation in the case of large-scale celebrations held on special occasions and involving not only a great number of the lay faithful, but also many concelebrating priests. On the one hand, it is easy to appreciate the importance of these moments, especially when the Bishop himself celebrates, surrounded by his presbyterate and by the deacons. On the other hand, it is not always easy in such cases to give clear expression to the unity of the presbyterate, especially during the Eucharistic Prayer and the distribution of Holy Communion. Efforts need to be made lest these large-scale concelebrations lose their proper focus. This can be done by proper coordination and by arranging the place of worship so that priests and lay faithful are truly able to participate fully. It should be kept in mind, however, that here we are speaking of exceptional concelebrations, limited to extraordinary situations.
Also see: Guidelines for Concelebration of the Eucharist, issued by the US Conference of Catholic Bishops November 12, 2003 (old.usccb.org/liturgy/concelebration.shtml).