[Solidarity] is 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. (St. John Paul II, On Social Concern [Sollicitudo rei Socialis],no.38)

Interdependence must be transformed into solidarity, based upon the principle that the goods of creation are meant for all. That which human industry produces through the processing of raw materials, with the contribution of work, must serve equally for the good of all. (St. John Paul II, On Social Concern [Sollicitudo rei Socialis], no. 39)

We have to move from our devotion to independence, through an understanding of interdependence, to a commitment to human solidarity. That challenge must find its realization in the kind of community we build among us. Love implies  concern for all - especially the poor - and a continued search for those social  and economic structures that permit everyone to share in a community that is a  part of a redeemed creation (Rom 8:21-23). (United States Conference of Catholic Bishops, Economic Justice for All, no. 365)

The solidarity which binds all men together as members of a common family makes it impossible for wealthy nations to look with indifference upon the hunger, misery and poverty of other nations whose citizens are unable to enjoy even elementary human rights. The nations of the world are becoming more and more dependent on one another and it will not be possible to preserve a lasting peace so long as glaring economic and social imbalances persist. (St. John XXIII, On Christianity and Social Progress [Mater et Magistra], no. 157)

To be continued