Comparison between the idea of Islam and liberalism about Justice (emphasizing on the idea of social contract and the idea of Mahdaviyat)

Justice is one of the important anxieties of all beliefs and religions which can be investigated from different aspects of abstract, philosophical and sociological. In this research we compare Islam and liberalism about the basis of Justice; to reach our goal, we investigate two ideas of social contract and Mahdaviyat Both of which have abstract thoughts and extended claim in this domain. The main question is that what is the difference between the basis of Justice in Islam and liberalism and based on that what ideas are made about Justice. The writer poses ,by analytic- comparative method, this theory that says justice in liberalism is partial and based on the idea ideas of citizens because it is based on the theory of social contract; as a result, there is no internal basis for justice. Consensus in every Affair is considered just and fair. And it's practical pattern is the political system of the United States of America. But in Islam and the idea of Mahdaviyat, based on monotheistic idea, Justice is based on internal affairs. The whole universe and being system is created on the basis of justice. And human beings Feel it by their nature. Madhavi Justice based on the idea of Mahdaviyat will be executed in all aspects by the appearance of Mahdi (peace be upon him). And because it is something natural, it has consensus. This issue can solve the most important problem of nowaday societies which is dissatisfaction of Justice.