Abstract: In his undergraduate thesis, “A Brief Inquiry into the Meaning of Sin and Faith”, John Rawls expressed his faith and understanding of religion as a young man. This thesis also demonstrates the close connection between his political philosophy and Christian ethics. The relationship among “A Brief Inquiry into the Meaning of Sin and Faith”, A theory of Justice and Political Liberalism shows that religion plays an important role in various ways in his political philosophy. Due to his early religious experience, Rawls reframed the traditional theory of social contract to built up a modern theory of justice. After recognizing the liberal neutrality’s failure to cope with religion’s challenge to political loyalty and political solidarity, Rawls put forward political liberalism to treat religion appropriately under the precondition that the fundamental of free constitution is guaranteed.

Key words: religion, justice, political liberalism, pluralism