While the term "social justice" means different things to different Christian and other religious organizations, an historic use of the concept in theological ethics was conjoined to a discussion of the common good that sought to explain the importance of private property, free enterprise, and the threat of big government.
On May 15, 1931, Pope Pius XI issued Quadragesimo anno (QA) to commemorate the 40th anniversary of Pope Leo XIII's encyclical Rerum Novarum. As explained by Christine Fiber Hinze in a commentary of QA, Pope Pius XI has been credited with introducing the term "social justice" into the lexicon of Christian ethics. When Protestants started using the term will require more research, but the Catholic usage was fairly easy to trace.
According to Hinze, Italian theologian Luigi Taparelli D'Azeglio introduced the term into Catholic social ethics in the mid-1800s to rearticulate potentially misunderstood concepts like "legal justice" and "general justice." Gustav Gunlac and Oswald von Nell-Breuning were particularly influential in inserting the language into QA. The concept was officially described later in 1937 in the encyclical Divini redemptoris, which attacked atheistic communism:
"[T]here [is] social justice with its own set obligations, from which neither employers nor workingmen can escape. Now it is of the very essence of social justice to demand for each individual all that is necessary for the common good. But just as in the living organism it is impossible to provide for the good of the whole unless each single part and each individual member is given what it needs for the exercise of its proper functions. . . . If social justice be satisfied, the result will be an intense activity in economic life as a whole, pursued in tranquillity and order."
For Pius XI in QA, social justice referred to the central and necessary set of conditions where each person makes free, non-government-coerced contributions to the common good. It included keeping in check the power of the State and the freedom of Christians to form their own institutions in civil society. It ensured that economics and morality were not alien to one another in concept or in practice. Social justice according to Pius XI referenced the necessity of private property against the tenets of socialistic thinking, because the right of private ownership not only enabled individuals "to provide for themselves and their families but also that the goods which the Creator destined for the entire family of mankind may through this institution truly serve this purpose." It mentioned the importance of wealth creation to provide a basis for charity and prohibitions against arbitrary wage demands by third-parties "which a business cannot stand without its ruin and consequent calamity to the workers." Pius XI's definition of social justice included the importance of subsidiarity and a return to the moral formation so that people would not confuse freedom to do good with passions that have been disordered because of original sin.
Social justice as a concept has not been a problem per se, but rather the problem lies in how it is defined. What we can say, based on historical reflection, is that any Christian articulation of social justice that seeks to hand the poor over to government for dependency and control is antithetical to the concept of justice within the history of Christianity.