20 Love of neighbour, grounded in the love of God, is first and foremost a responsibility for each individual member of the faithful, but it is also a responsibility for the entire ecclesial community at every level: from the local community to the particular Church and to the Church universal in its entirety. As a community, the Church must practise love. Love thus needs to be organized if it is to be an ordered service to the community. The awareness of this responsibility has had a constitutive relevance in the Church from the beginning: “All who believed were together and had all things in common; and they sold their possessions and goods and distributed them to all, as any had need” ( Acts 2:44-5). In these words, Saint Luke provides a kind of definition of the Church, whose constitutive elements include fidelity to the “teaching of the Apostles”, “communion” ( koinonia ), “the breaking of the bread” and “prayer” (cf. Acts 2:42). The element of “communion” ( koinonia ) is not initially defined, but appears concretely in the verses quoted above: it consists in the fact that believers hold all things in common and that among them, there is no longer any distinction between rich and poor (cf. also Acts 4:32-37). As the Church grew, this radical form of material communion could not in fact be preserved. But its essential core remained: within the community of believers there can never be room for a poverty that denies anyone what is needed for a dignified life.
Source: Deus Caritas Est (Vatican.va)