God, in Christ, redeems not only the individual person but also the social relations existing between men. As the Apostle Paul teaches, life in Christ makes the human person's identity and social sense — with their concrete consequences on the historical and social planes — emerge fully and in a new manner: “For in Christ Jesus you are all children of God, through faith. For as many of you as were baptized into Christ have put on Christ. There is neither Jew nor Greek, neither slave nor free, there is neither male nor female; for you are all one in Christ” (Gal 3:26-28). In this perspective, Church communities, brought together by the message of Jesus Christ and gathered in the Holy Spirit round the Risen Lord (cf. Mt 18:20, 28:19-20; Lk 24:46-49), offer themselves as places of communion, witness and mission, and as catalysts for the redemption and transformation of social relationships.
The transformation of social relationships that responds to the demands of the Kingdom of God is not fixed within concrete boundaries once and for all. Rather, it is a task entrusted to the Christian community, which is to develop it and carry it out through reflection and practices inspired by the Gospel. It is the same Spirit of the Lord, leading the people of God while simultaneously permeating the universe63Cf. Second Vatican Ecumenical Council, Gaudium et Spes, 11: AAS 58 (1966), 1033., who from time to time inspires new and appropriate ways for humanity to exercise its creative responsibility64Cf. Paul VI, Apostolic Letter Octogesima Adveniens, 37: AAS 63 (1971), 426-427.. This inspiration is given to the community of Christians who are a part of the world and of history, and who are therefore open to dialogue with all people of good will in the common quest for the seeds of truth and freedom sown in the vast field of humanity65Cf. John Paul II, Encyclical Letter Redemptor Hominis, 11: AAS 71 (1979), 276: “The Fathers of the Church rightly saw in the various religions as it were so many reflections of the one truth, ‘seeds of the Word', attesting that, though the routes taken may be different, there is but a single goal to which is directed the deepest aspiration of the human spirit”.. The dynamics of this renewal must be firmly anchored in the unchangeable principles of the natural law, inscribed by God the Creator in each of his creatures (cf. Rom 2:14-15), and bathed in eschatological light through Jesus Christ.
Jesus Christ reveals to us that “God is love” (1 Jn 4:8) and he teaches us that “the fundamental law of human perfection, and consequently of the transformation of the world, is the new commandment of love. He assures those who trust in the love of God that the way of love is open to all people and that the effort to establish a universal brotherhood will not be in vain”66Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 38: AAS 58 (1966), 1055-1056.. This law is called to become the ultimate measure and rule of every dynamic related to human relations. In short, it is the very mystery of God, Trinitarian Love, that is the basis of the meaning and value of the person, of social relations, of human activity in the world, insofar as humanity has received the revelation of this and a share in it through Christ in his Spirit.
The transformation of the world is a fundamental requirement of our time also. To this need the Church's social Magisterium intends to offer the responses called for by the signs of the times, pointing above all to the mutual love between human beings, in the sight of God, as the most powerful instrument of change, on the personal and social levels. Mutual love, in fact, sharing in the infinite love of God, is humanity's authentic purpose, both historical and transcendent. Therefore, “earthly progress must be carefully distinguished from the growth of Christ's kingdom. Nevertheless, to the extent that the former can contribute to the better ordering of human society, it is of vital concern to the kingdom of God”67Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 39: AAS 58 (1966), 1057..