This is a huge subject, with many areas to cover, so this is by necessity, a brief overview to provoke thought and debate.
From Wikipedia -
Making a fair world as far as it is possible.
Violence is wrong.
Do we want hungry, poor, ill-
If we do better at the expense of anyone else, that is injustice.
Equal pay for equal work
The unfairness that is in discrimination on race, gender, age etc.
Freedoms of expression, assembly etc.
If we take greedily, with no conscience or care of harm, then an injustice has been done.
We have the goal of being unhindered by state and religious institutions – any manipulations and deviations from these – are immoral.
The state by definition is the embodiment of the people and operates with their consent to fulfil the duties and obligations entrusted to it. Each citizen should demand that this is case with no equivocation.
Distilling all that went before:
The Universal Declaration of Human Rights, which was adopted by the UN General Assembly on 10 December 1948.
Look at the French and American revolutions and their intent in regard to social justice. They strived to provide a clear framework to promote true citizenship and define relations within the country and to other lands by means of Liberty, Equality, and Fraternity with civil justice, criminal justice and rights & responsibilities. Yes they came about through violent explosions of anger and overthrowing of established systems of government – but this is not necessary now. Gandhi’s ideal shows this.
Conflicting ideas, both spiritual and temporal, should never overrule the feeling of a moral code that ensures “do no harm”. Harm to one is harm to all. So legality and ethical behaviour are inherent in this higher imperative.
Ideals founder on the rocks of human ego unless tempered by collective watchfulness. We all are important, have to feel important and act decisively to retain the concept of social justice.
All are equal in being human. Our abilities will differ, our tastes will differ but even then we are the same and, as brothers and sisters in a global family, we should care for each other. We must contribute to the common good and embrace the potential of all. Any less is a diminishment of us all. We are one. Feel that, believe that and know that. Then we will change the world for the better.
Nice list of ideas
Thomas Paine The rights of man
UN declaration of Human rights