John 17: 22- The glory which you have given me I have given to them, that they may be one even as we are one, I in them and you in me, that they may become perfectly one.
Jesus gives us a challenging human vocation: to share divine interpersonal communication, to be a human community in the image of the three-in-one.
Movement-toward-the-other is characteristic of divine personality, and it is the ultimate pattern for all relationships.
According to St. Augustine (De Trinitate), the immanent life of God is described in terms of
Processions: Meaning the Son's eternal birth from the Father and the Holy Spirit's proceeding from the Father and the Son
Missions: Meaning the manifestations of these eternal processions in creation
Names: Designating three-in-one
Relationships: Paternity, Filiation, Passive Spiration
According to St. Augustine, that which distinguishes the persons in God is precisely their relations. The persons are not the relations themselves but the unchangeable relations is what expresses their distinctiveness of persons.
To bring this mystery of the trinity to life St. Augustine sought examples of "trinities" within human experience, "Now love is of someone who loves and something is loved with love. So then there are three: the lover, the beloved, and the love." In divine identity, the "love" is most appropriately called the "Holy Spirit."