The celebration of the Eucharist is the action of Christ and of the Church, namely,
of the holy people united and ordered under the Bishop. It therefore pertains to the whole Body of the Church, manifests it, and has its effect upon it. Indeed, it also affects the individual members of the Church in a different way, according to their different orders, functions, and actual participation. In this way, the Christian people, ‘a chosen race, a royal priesthood, a holy nation, a people for his own possession’, expresses its cohesion and its hierarchical ordering. All, therefore, whether ordained ministers or lay Christian faithful, in fulfilling their function or their duty, should carry out solely but totally that which pertains to them. – GIRM #9