The religio-ethical tradition that political theology relies on does not directly relate to socio-political praxis. It depends on social theories to establish its relation with praxis. Harbermas' social theory provides a theoretical framework to connect political theology and political praxis. In Habermas' opinion, moral regulation should be established through public discussion. However, his theory on modernity has ignored three fundamental changes that religion has had in modern society. Subsequently, he treats religious beliefs as obsolete worldviews buttressed by traditional forms of authority. Seeing the limits in Harbermas' theory on discourse ethics, this essay argues that religious tradition has intrinsic regulatory content, so the church as an interpretative community can enter the modern pluralistic public sphere of discourse and provide a foundation for the system of public discussion on ethical issues.