The article is dedicated to one of the most relevant issues in religious thought—the preservation of church tradition. The interest in this issue became particularly acute for Russian religious thinkers of the 20th century, who witnessed radical changes in living conditions and collective consciousness. The article examines the interpretation of the issue in the works by Sergey Fudel (1900–1977), a church writer and carrier of pre-revolutionary Russian culture. He had communication with outstanding spiritual figures spanning the late 19th to the 20th centuries, confessors of faith, and new martyrs. The church and historical context of Fudel’s works is explored, clarifying the connection between the writer’s views on the transmission of church tradition, his own biography, the figures of his mentors, and the existence conditions for the persecuted Church, evidenced in Fudel’s writings. The article sheds light on the writer’s response to changes in the conditions of church life in the mid-20th century and the feeling of a “generation gap” that emerged in him. It reconstructs Fudel’s notion of the “monastery in the world” as an environment where church tradition is preserved. The correlation between Fudel’s concept of church tradition and his ecclesiological views is illuminated. The research findings lead to the conclusion that the phenomenon of the “hidden Church” as an alliance of “two or three” disciples of Christ was not, in Fudel’s view, a temporary solution stemming from the era of persecutions. Instead, the writer regarded such an experience as an exposition of the Church’s original teaching about itself and an enduring model of church relations. Like many others, Fudel acknowledged the providential significance of trials undergone by the Russian Church. However, he insisted that the experience of the “hidden Church” revealed the original teaching of the Church about itself, preserved throughout the ages. The article also considers the relationship between Fudel’s views and other approaches to the “generation gap” problem. Fudel’s evaluation of previous eras, marked by the “external prosperity” of Christianity, allows characterization of his attitude towards various concepts of tradition, both classical, tracing back to the times of the Byzantine Empire, and those contemporary to the writer.