The article is structured around the idea that the Church is born from the Holy Trinity in the paschal mystery and in the Ressurection memorial celebration. Following this central idea, the author is developing the ontology of the Church, taking into account the Eucharist’s ontology, and he draws attention to some present temptations that threaten the ontological identity of the Church. Thus, starting from the fact that the Eucharist is the memorial of the beginning and the Church is „born of Trinity”, the author underlines three dimensions of the Church, which are based on three elements of its reality: mystery, but implication also. Secondly, after prooving that the Eucharist is the paschal feast and the Church is the „communio sanctorum”, the author makes a link between the icon of the Trinity and the pastoral perichoresis, underlining the fact that the whole Church is charismatical and ministerial. Finally, because the Eucharist is the guarantee of the future glory and the Church is walking on the Kingdom’s way, the eucharistical Church is „semper reformanda” (always progressing, changing) and in the same time she must become the critical conscience of the history and the witness of the Beauty that redeems.