While there are some delicate differences between Hume's Treatise of Human Nature and his Enquiry Concerning the Principles of Morals, to take these differences seriously is essential to an adequate understanding of Hume's moral thought. This essay examines Hume's ideas of justice and benevolence elaborated in those works. My main contention is that the differences between the two works are caused not by Hume's revision of his theory under the pressure of public opinion, but by the change of the perspective from which he observes virtues, namely his focus has been transferred from the different origins of virtues to the utility they bring about. In spite of the differences, however, the nature of Hume's theory remains the same. Hume is faithful to his position as an anatomist of human nature, and his aim is to provide a descriptive rather than prescriptive theory.