In the present condition of global society, where injustices abound and growing numbers of people are deprived of basic human rights and considered expendable, the principle of the common good immediately becomes, logically and inevitably, a summons to solidarity and a preferential option for the poorest of our brothers and sisters. This option entails recognizing the implications of the universal destination of the world's goods, but, as I mentioned in the Apostolic Exhortation Evangelii Gaudium, it demands before all else an appreciation of the immense dignity of the poor in the light of our deepest convictions as believers. We need only look around us to see that, today, this option is in fact an ethical imperative essential for effectively attaining the common good. (Pope Francis, On Care for Our Common Home [Laudato Si'], no. 158)

To love someone is to desire that person's good and to take effective steps to secure it.  Besides the good of the individual, there is the good that is linked to living in society: the common good.  It is the good of "all of us", made up of individuals, families and intermediate groups who together constitute society.  … To desire the common good and strive towards it is a requirement of justice and charity. (Pope Benedict XVI, Charity in Truth [Caritas in Veritate], no. 7)

It is good for people to realize that purchasing is always a moral — and not simply economic — act. Hence the consumer has a specific social responsibility, which goes hand-in- hand with the social responsibility of the enterprise. Consumers should be continually educated regarding their daily role, which can be exercised with respect for moral principles without diminishing the intrinsic economic rationality of the act of purchasing… It can be helpful to promote new ways of marketing products from deprived areas of the world, so as to guarantee their producers a decent return. (Pope Benedict XVI, Charity in Truth [Caritas in Veritate], no. 66)

At another level, the roots of the  contradiction between the solemn affirmation of human rights and their tragic  denial in practice lies in a notion of freedom which exalts the isolated  individual in an absolute way, and gives no place to solidarity, to openness to  others and service of them. . . It is precisely in this sense that Cain's answer to the Lord's question: "Where is Abel your brother?" can be interpreted: "I do not know; am I my brother's keeper?" (Gen 4:9).  Yes, every man is his "brother's keeper", because God entrusts us to one another. (St. John Paul II, The Gospel of Life [Evangelium Vitae], no. 19)

To be continued