Spinoza and Hume are two naturalist philosophers who were among the first modern thinkers to study religion as a natural phenomenon. There undoubtedly are similarities in their accounts of the origin of religion in imagination and passion (emotion). But those who see Hume as a crypto-Spinozist are nevertheless confronted with serious differences between the two philosophers with respect to their understanding of religion and its various forms. These differences concern fundamental issues like the meaning and acceptability of the notion of God and its function in different spheres, the possibility of a kind of philosophical religiosity, and the possible advantage of religion, at least in some of its forms, to individual and social life. The militant "Spinozism" of Hume belongs to a world perhaps (in part) made possible by Spinoza, but nevertheless alien to him.