Participation in the liturgy, is defined yet again as an act that involves “all.”
51. There is a need too to ensure that all those present, children and adults, take an active interest, by encouraging their involvement at those points where the liturgy suggests and recommends it.(Cf. Sacrosanctum Concilium 14; 26; John Paul II, Apostolic Letter Vicesimus Quintus Annus (4 December 1988), 4; 6; 12: AAS 81 (1989), 900-901; 902; 909-910) Of course, it falls only to those who exercise the priestly ministry to effect the Eucharistic Sacrifice and to offer it to God in the name of the whole people.(Cf. Lumen Gentium 10) This is the basis of the distinction, which is much more than a matter of discipline, between the task proper to the celebrant and that which belongs to deacons and the non-ordained faithful.(Cf. Interdicasterial Instruction on Certain Questions concerning the Collaboration of Lay Faithful in the Ministry of Priests Ecclesiae de Mysterio (15 August 1997), 6; 8: AAS 89 (1997), 869; 870-872) Yet the faithful must realize that, because of the common priesthood received in Baptism, “they participate in the offering of the Eucharist”.(Lumen Gentium 10: “in oblationem Eucharistiae concurrunt“) Although there is a distinction of roles, they still “offer to God the divine victim and themselves with him. Offering the sacrifice and receiving holy communion, they take part actively in the liturgy”,(Lumen Gentium 11) finding in it light and strength to live their baptismal priesthood and the witness of a holy life.
The almost vehement insistence on preserving the role of the priest (which has never been in any significant danger) is here too, of course. Yet all the baptized offer sacrifice. Can’t avoid it.
And to be sure, nobody is forced to offer sacrifice. The Lord accepts people just coming, just seeking, just crossing their arms and waiting. The invitation to participate, and leaving spaces empty where they need to be left so–this should be a constant. Just like Sunday as a whole. We are invited to participate in Sunday, yet many of us do not.