The article is devoted to the exploration of spiritual and religious principles in the works of Johannes Brahms and their manifestation in the composer’s vocal and choral opuses. The aim of the study is to reveal the spiritual, ethical, and religious foundations of Brahms’ creative personality and their reflection in the composer’s vocal heritage (using A German Requiem and the vocal cycle Four Serious Songs as examples). The methodology combines intonational, genre-stylistic, etymological, and hermeneutical approaches. The scientific novelty of the study is marked by the introduction into musicology of not only materials concerning the religious worldview of Brahms but also their influence on the formation of the conceptual content inherent in his works, shaped at the intersection of Protestant-Lutheran principles of the German cultural-historical tradition and their metamorphoses during the spiritual quests of the Romantic era. The findings show that the generalization of bibliographic and analytical sources on Brahms’ works, including his vocal heritage, reveals the depth of the spiritual, ethical, and religious principles of his creative personality, which trace back to the German Protestant tradition and the culture formed on its basis. At the same time, these principles were enriched by the spiritual searches of German Romanticism and the Biedermeier period. The appeal to the age-old principles of past national culture and its illustrious representatives, combined with the revival of the “spirit” of the nation and the characteristic Protestant convergence and mutual spiritualization of sacred and secular genres, contributed to the consolidation of German society and its movement towards the unification of Germany. These aspects are also reflected in the poetics of Brahms’ A German Requiem and the vocal cycle Four Serious Songs, which exhibit the tradition’s characteristic focus on eternal themes of life and death in their Protestant interpretation, the use of relevant biblical texts and their authorial re-interpretation, as well as the appeal to the “intonational dictionary” of the Protestant chorale, ranging from direct citation to free compositional realization of broadly interpreted chorality.