54 The theme of development can be identified with the inclusion-in-relation of all individuals and peoples within the one community of the human family, built in solidarity on the basis of the fundamental values of justice and peace. This perspective is illuminated in a striking way by the relationship between the Persons of the Trinity within the one divine Substance. The Trinity is absolute unity insofar as the three divine Persons are pure relationality. The reciprocal transparency among the divine Persons is total and the bond between each of them complete, since they constitute a unique and absolute unity. God desires to incorporate us into this reality of communion as well: “that they may be one even as we are one” (Jn 17:22). The Church is a sign and instrument of this unity . Relationships between human beings throughout history cannot but be enriched by reference to this divine model. In particular, in the light of the revealed mystery of the Trinity , we understand that true openness does not mean loss of individual identity but profound interpenetration. This also emerges from the common human experiences of love and truth. Just as the sacramental love of spouses unites them spiritually in “one flesh” (Gen 2:24; Mt 19:5; Eph 5:31) and makes out of the two a real and relational unity, so in an analogous way truth unites spirits and causes them to think in unison, attracting them as a unity to itself.
Source: Caritas in Veritate (Vatican.va)