An examination of Joseph Haydn's 1767 setting of the Stabat Mater reveals a masterpiece of profound depth. Much has been written about the style and musical architecture of Haydn's music, however, very little has been written about this opus in its entirety. This study examines the history of lament or Planctus Mariae, from which the poem of the Stabat Mater sprang, briefly studies some of the musical antecedents to the 1767 setting, and illuminates the various musical gestures, forms, and tonal architecture, within the context of Haydn's Stabat Mater. This study shows that imitative forms like canon and fugue, text painting, and the harmonic underpinning of the various movements, when viewed within the context of the planctus tradition, all work together to provide a musical pathos whose sole aim is to make listeners and performers unite in feeling the pain of the Virgin and her Son. When contextualized this way, Haydn's Stabat Mater emerges in a completely new light, and the question of empathy can be understood, not just by the text and the history of the tradition of lament, but by becoming fully immersed in rhetorical resources of the music.