In Islam, justice is to be applied to everyone, rich and poor, young and old, ally and enemy, Muslim and non-Muslim and so forth.
The establishment of justice and working for justice is one of the heavy responsibilities upon the Muslim community as a whole.
This results from Islam or the true submission to Allah alone. This is the only way of life consistent with the nature of human beings.
"And that when you judge between men, you judge with justice" (Quran 4: 58).