With the unceasing amazement of those who have experienced the inexpressible love of God (cf. Rom 8:26), the New Testament grasps, in the light of the full revelation of Trinitarian love offered by the Passover of Jesus Christ, the ultimate meaning of the Incarnation of the Son and his mission among men and women. Saint Paul writes: “If God is for us, who is against us? He who did not spare his own Son but gave him up for us all, will he not also give us all things with him?” (Rom 8:31-32). Similar language is used also by Saint John: “In this is love, not that we loved God but that he loved us and sent his Son to be the expiation for our sins” (1 Jn 4:10).
The Face of God, progressively revealed in the history of salvation, shines in its fullness in the Face of Jesus Christ crucified and risen from the dead. God is Trinity: Father, Son, and Holy Spirit; truly distinct and truly one, because God is an infinite communion of love. God's gratuitous love for humanity is revealed, before anything else, as love springing from the Father, from whom everything draws its source; as the free communication that the Son makes of this love, giving himself anew to the Father and giving himself to mankind; as the ever new fruitfulness of divine love that the Holy Spirit pours forth into the hearts of men (cf. Rom 5:5). By his words and deeds, and fully and definitively by his death and resurrection30Cf. Second Vatican Ecumenical Council, Dogmatic Constitution Dei Verbum, 4: AAS 58 (1966), 819., Jesus reveals to humanity that God is Father and that we are all called by grace to become his children in the Spirit (cf. Rom 8:15; Gal 4:6), and therefore brothers and sisters among ourselves. It is for this reason that the Church firmly believes that “the key, the centre and the purpose of the whole of man's history is to be found in her Lord and Master”31Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 10: AAS 58 (1966), 1033..
Meditating on the gratuitousness and superabundance of the Father's divine gift of the Son, which Jesus taught and bore witness to by giving his life for us, the Apostle John grasps its profound meaning and its most logical consequence. “Beloved, if God so loves us, we also ought to love one another. No man has ever seen God; if we love one another, God abides in us and his love is perfected in us” (1 Jn 4:11-12). The reciprocity of love is required by the commandment that Jesus describes as “new” and as “his”: “that you love one another; even as I have loved you, that you also love one another” (Jn 13:34). The commandment of mutual love shows how to live in Christ the Trinitarian life within the Church, the Body of Christ, and how to transform history until it reaches its fulfilment in the heavenly Jerusalem.
The commandment of mutual love, which represents the law of life for God's people32Cf. Second Vatican Ecumenical Council, Dogmatic Constitution Lumen Gentium, 9: AAS 57 (1965), 12-14., must inspire, purify and elevate all human relationships in society and in politics. “To be human means to be called to interpersonal communion”33John Paul II, Apostolic Letter Mulieris Dignitatem, 7: AAS 80 (1988), 1666., because the image and the likeness of the Trinitarian God are the basis of the whole of “human ‘ethos', which reaches its apex in the commandment of love”34John Paul II, Apostolic Letter Mulieris Dignitatem, 7: AAS 80 (1988), 1665-1666.. The modern cultural, social, economic and political phenomenon of interdependence, which intensifies and makes particularly evident the bonds that unite the human family, accentuates once more, in the light of Revelation, “a new model of the unity of the human race, which must ultimately inspire our solidarity. This supreme model of unity, which is a reflection of the intimate life of God, one God in three Persons, is what we Christians mean by the word 'communion'”35John Paul II, Encyclical Letter Sollicitudo Rei Socialis, 40: AAS 80 (1988), 569.. III. THE HUMAN PERSON IN GOD'S PLAN OF LOVE