The subject of the celebration is a plural subject, which acts according to its proper function, in order to give a better manifestation of the central invisible subject, who is Christ, and so to give a better participation in the praise of God and for the sanctification of the People of God. Each type of celebration demands a proper subject, although in every celebration Christ is always the real priest and the Church is always the necessary mediation associated with Christ. Our aim is to analyse, to give the foundation of and to apply the subject of the celebration, bearing in mind the plurality and complimentary of celebrative sitations. Our method will be to start off with the "most" important or significant subject (Christ) and, from him, to go on to interpret the "less" important or significant subjects (Church, assembly, ordained ministers, other lay ministries).