The Thesis wants to demonstrate the theological foundations that propose Ecclesiology of Communion for the Unit, based in the writings of Teresa de Lisieux, especially in her book Story of a Soul, and in the Theology of Johann-Adam Mohler about the Unit in the Church. We ll do a reinterpretation of the Communion Ecclesiology of Vatican II. We will explore some aspects like the Centralism of Love lived and experienced by the multitude of small souls who form the Church, presented by Teresa de Lisieux, and the argument about the Unit in the Church in the perspective of Communion by Johann-Adam Mohler, in accordance with his concrete experience. We will try to present this Ecclesial Unit taking from the notion of Multitude of Faithful in the book of Acts of the Apostles: And the multitude of them which believed were one heart and one soul (Acts 4, 32). Having an ecclesial configuration which involves all peoples in view of the universality of salvation and the multiform modes of services and ministries. We ll retake the notion of the Church as the Body of Christ presented in Patristic Theology and in the Magisterium of the Church, also present in the Doctrine of Vatican II, in consonance with the notion of God s People. The diversity of the members of this Body, for its interrelation and coverage, must be spread over all humanity, now understood as multitude of the faithful. The Unit in the Church became, in current times, one of the most significant aspects for Theology, precisely because, the character of universality of salvation and the relational expressivity between people worldwide, need of one theological grounding in the perspective of Religious Unit and the Dialogue against multiple initiatives.