Research on the use of the Dies irae quotation in Western European and Russian music, including Rachmaninoff’s, typically sees exclusively negative symbolism. However, in the texts of the prototypes of the “Last Judgment”—the Book of Zephaniah and the medieval sequence—alongside words of terrible retribution, there is also a narrative of God’s mercy. S. V. Rachmaninoff himself, according to the memoirs of I. S. Yasser, believed that the theme of the Catholic sequence concealed something more than death. Using the example of the third movement of the “Symphonic Dances,” it is shown that by combining the melody of the Dies irae with the intonations of the Znamenny minor chant, a new musical theme emerges. And the symbolism of the Last Judgment is perceived here not so much as a terrible event, but as the reign of justice, in which, through the immeasurable mercy of God, people are given hope for salvation.