Some recent studies of religion show that the concept of 'religion' is formed through the historical practices of modern Europe and what is called 'the essence of religion' is only a historical construct. This paper draws a comparison between Paul Tillich and Ernst Cassirer from the view of their concepts of religion. Tillich, who is a transcendent realist, considers religion to be the essence of culture, constructed by the religious reality and cultural functions of human beings. Cassirer, a critical idealist, thinks that religion is differentiated from myth, an original symbolic form of the human spirit, and becomes independent and autonomous as a cultural field in which emotion makes a critical role. Their concepts of religion differ, but they are alike in their conceptual arrangement. They suggest that emotion and culture are two critical points of religion in the modern age.