Social Justice, also known as economic justice, is a term describing the redistribution of wealth for the common good of all. However, this comes at the expense of wage earners and liberty by demanding a society to conform. Those who work and have must give to those who don't work and don't have. This is the fundamental basis of Marxism and championed by liberal progressives. Everyone shall have equal advantages and everyone will have equal disadvantages. In reality it creates two classes, those with power and everyone else.
Many Christian organizations strongly support social justice. However, this is a trap promoted by liberal Christianity claiming Jesus was a socialist. We are to help the less fortunate but we are not to become the less fortunate in the process. We are to give according to our abilities but social justice violates "thou shall not steal" and takes what is yours. The National Council of Churches, the group that translates the Bible to the New Revised Standard Version, is an advocate of Social Justice. 
The Roman Catholic Church and Social Justice
The Roman Catholic Church advocates social justice that is based on charity and support for all mankind, its key points being respect for the human person, equality and difference among men, human solidarity. In brief, they seek respect, equal dignity, encourage charity, reduce excessive social and economic inequalities, the elimination of sinful inequalities, and the sharing of spiritual goods. 
The Church's support of the teaching began largely with Rerum Novarum, an encyclical letter written by Pope Leo XIII, published in 1891. The 1962 - 1965 Second Vatican Council produced an Apostolic Constitution called Gaudium et Spes which stated in Paragraph 90:
"The council, considering the immensity of the hardships which still afflict the greater part of mankind today, regards it as most opportune that an organism of the universal Church be set up in order that both the justice and love of Christ toward the poor might be developed everywhere. The role of such an organism would be to stimulate the Catholic community to promote progress in needy regions and international social justice."
Based on the above statement, in 1967 Pope Paul VI created a Pontifical Commission called Justice and Peace, later re-named by Pope John Paul II The Pontifical Council for Justice and Peace.
- Glenn Beck Keeps 'Social Justice' Debate Alive Christian Post, March 20, 2010
- Vatican- Social Justice