Rodger Charles S.J. wrote what, in my opinion, is the single best introduction of the social teaching of the Church in its entirety, and where his approach is different from many writing about the social teaching, he makes it clear that it is a teaching with a history that began with Genesis.
His two volume work was published in Great Britain in 1998, Christian Social Witness and Teaching: The Catholic Tradition from Genesis to Centesimus Annus (Volume 1) From Biblical Times to the Late Nineteenth Century & (Volume 2) The Modern Social Teaching Contexts: Summaries: Analysis.
An excellent review of the work is at the Acton Institute’s Journal of Markets & Morality.
The best place to find both volumes is through Abe Books, or you can go through the publisher, Gracewing Publishing.
Here is an excerpt from Volume 1.
“Like the Old Testament, the New spoke of man made in God’s image, but now he was in a new relationship with God, taken up into Christ and therefore into the life of God himself. The parable of the vine and the branches (John 15: 5-6) brings this out. St. Paul extended this parallel using the example of the human body. It is made up of many parts but is none the less one body; so it is with Christ’s mystical body, the Church. ‘In one spirit we were baptized, Jews as well as Greeks, slaves as well as citizens’ (1 Cor.12:12-30, Rom. 12: 4-8, Eph. 4: 11-13).
“The kingdom, then, is vivified by the life of Christ, and his Church is its first budding forth on earth, though potentially it embraces all mankind. The Gospel which united man to his God therefore was also a Gospel of solidarity and brotherhood. It encourages its citizens toward mutual association and these characteristics of its history are not accidental. There is a natural instinct which draws mankind to mutual co-operation; he is a social being. But membership of the Church raises the social connection of human beings from the sphere of convention to that of moral obligation.
“Charity among men, as a duty stemming from love of God, follows; the parable of the Good Samaritan and its practical implications demonstrate this most fully. (Luke 10: 29-37). Christ was talking about solidarity with his suffering brethren whoever they are, not only those of the Jews. ‘I was hungry and you gave me food, thirsty and you gave me drink, I was a stranger and you made me welcome, naked and you clothed me, sick and you visited me…’ (Matt. 25: 35-46). This new aspect of the theology of benevolence has been the basis of Christian works of charity in which the Church has been outstanding from the earliest times. In the long term, and peacefully, this kingdom, purely spiritual and moral though it was, was to exercise immense influence on earth, precisely because it did not seek access to direct political power. This is the paradox of the kingdom of God in terms of the social order, of ethics and civil society. There was in the Gospel a message of solidarity and brotherhood, an impulse to mutual association which was not accidental or peripheral to it. It spiritualized all that was best in man’s social nature, the impulse that draws us to one another and endows what had been simple social convention with the character of moral obligation.
“It does this through the grace of Christ. He is the vine, we are the branches. The human race, human society, is bound up into his mystical body—which is not only the Church, though it is the Church primarily; secondarily but no less really it is all mankind, whether mankind knows it or not. There is in us a supernatural life, and through us as social beings that life permeates human society also. This bond between men is capable of being stronger than any merely human bond. It should bind us together from the time we come into human society through the most basic of its forms, the family. It should teach us that man is more to be valued for what he is than for what he has, to protect the poor and defend their rights and dignity. It should enable the rich to use their riches for God’s glory and the service of others as well as for their own honest enjoyment, and warns of the spiritual dangers wealth can bring.
“If we let it, it provides in sum the principles and ideals on which a healthy human society can be based; it exhorts us to pray that the kingdom will come on earth and that the Father’s will be done here as it is in heaven, and through grace it gives us the power to do this. Fulfilled as it will be only in eternity, the kingdom none the less begins on earth and helps inspire human society to charity and justice. It secures for us the means to self-giving because the Christ in whose life we live gave himself of us. It bases human rights on man’s dignity as made in God’s image and likeness, and it establishes human freedom in the context of the divine and natural laws which alone can ensure the true happiness and fulfillment which men and women seek.” (Volume 1, pp. 32-33)