a. Meaning and value
192. Solidarity highlights in a particular way the intrinsic social nature of the human person, the equality of all in dignity and rights and the common path of individuals and peoples towards an ever more committed unity. Never before has there been such a widespread awareness of the bond of interdependence between individuals and peoples, which is found at every level . The very rapid expansion in ways and means of communication “in real time”, such as those offered by information technology, the extraordinary advances in computer technology, the increased volume of commerce and information exchange all bear witness to the fact that, for the first time since the beginning of human history, it is now possible — at least technically — to establish relationships between people who are separated by great distances and are unknown to each other.
In the presence of the phenomenon of interdependence and its constant expansion, however, there persist in every part of the world stark inequalities between developed and developing countries, inequalities stoked also by various forms of exploitation, oppression and corruption that have a negative influence on the internal and international life of many States. The acceleration of interdependence between persons and peoples needs to be accompanied by equally intense efforts on the ethical-social plane, in order to avoid the dangerous consequences of perpetrating injustice on a global scale. This would have very negative repercussions even in the very countries that are presently more advantaged .
b. Solidarity as a social principle and a moral virtue
193. The new relationships of interdependence between individuals and peoples, which are de facto forms of solidarity, have to be transformed into relationships tending towards genuine ethical-social solidarity. This is a moral requirement inherent within all human relationships. Solidarity is seen therefore under two complementary aspects: that of a social principle  and that of a moral virtue .
Solidarity must be seen above all in its value as a moral virtue that determines the order of institutions. On the basis of this principle the “structures of sin”  that dominate relationships between individuals and peoples must be overcome. They must be purified and transformed into structures of solidarity through the creation or appropriate modification of laws, market regulations, and juridical systems.
Solidarity is also an authentic moral virtue, not a “feeling of vague compassion or shallow distress at the misfortunes of so many people, both near and far. On the contrary, it is a firm and persevering determination to commit oneself to the common good. That is to say to the good of all and of each individual, because we are all really responsible for all” . Solidarity rises to the rank of fundamental social virtue since it places itself in the sphere of justice. It is a virtue directed par excellence to the common good, and is found in “a commitment to the good of one's neighbor with the readiness, in the Gospel sense, to ‘lose oneself' for the sake of the other instead of exploiting him, and to ‘serve him' instead of oppressing him for one's own advantage (cf. Mt 10:40-42, 20:25; Mk 10:42-45; Lk 22:25-27)”.
c. Solidarity and the common growth of mankind
194. The message of the Church's social doctrine regarding solidarity clearly shows that there exists an intimate bond between solidarity and the common good, between solidarity and the universal destination of goods, between solidarity and equality among men and peoples, between solidarity and peace in the world . The term “solidarity”, widely used by the Magisterium , expresses in summary fashion the need to recognize in the composite ties that unite men and social groups among themselves, the space given to human freedom for common growth in which all share and in which they participate. The commitment to this goal is translated into the positive contribution of seeing that nothing is lacking in the common cause and also of seeking points of possible agreement where attitudes of separation and fragmentation prevail. It translates into the willingness to give oneself for the good of one's neighbor, beyond any individual or particular interest .
195. The principle of solidarity requires that men and women of our day cultivate a greater awareness that they are debtors of the society of which they have become part. They are debtors because of those conditions that make human existence livable, and because of the indivisible and indispensable legacy constituted by culture, scientific and found in “a commitment to the good of one's neighbor with the readiness, in the Gospel sense, to ‘lose oneself' for the sake of the other instead of exploiting him, and to ‘serve him' instead of oppressing him for one's own advantage (cf. Mt 10:40-42, 20:25; Mk 10:42-45; Lk 22:25-27)”.
d. Solidarity in the life and message of Jesus Christ
196. The unsurpassed apex of the perspective indicated here is the life of Jesus of Nazareth, the New Man, who is one with humanity even to the point of “death on a cross” (Phil 2:8). In him it is always possible to recognize the living sign of that measureless and transcendent love of God-with-us, who takes on the infirmities of his people, walks with them, saves them and makes them one. In him and thanks to him, life in society too, despite all its contradictions and ambiguities, can be rediscovered as a place of life and hope, in that it is a sign of grace that is continuously offered to all and because it is an invitation to ever higher and more involved forms of sharing.
Jesus of Nazareth makes the connection between solidarity and charity shine brightly before all, illuminating the entire meaning of this connection : “In the light of faith, solidarity seeks to go beyond itself, to take on the specifically Christian dimensions of total gratuity, forgiveness and reconciliation. One's neighbor is then not only a human being with his or her own rights and a fundamental equality with everyone else, but becomes the living image of God the Father, redeemed by the blood of Jesus Christ and placed under the permanent action of the Holy Spirit. One's neighbor must therefore be loved, even if an enemy, with the same love with which the Lord loves him or her; and for that person's sake one must be ready for sacrifice, even the ultimate one: to lay down one's life for the brethren (cf. 1 Jn 3:16)”.