Abstract: The book “The Venerable Sergius of Radonezh” by Boris Konstantinovich was first published in Paris in 1925. A. V. Amfiteatrov-Kadashev assumed that it is “the best work of the writer, imbued with the warmth of humanism, but, at the same time, truly national, Russian in spirit”. It is hard to disagree with this statement: B. K. Zaitsev not only describes the path of the Venerable Sergius of Radonezh, but also reflects a peculiar concept of the Russian sanctity. The fate Sergius of Radonezh resembles the path of Russia. The key traits of the true national character, the Russian soul merged in the image of the venerable old man. His image embodied the idea of the sanctity of the Ancient Rus’ and modern Russia – inwardly and spiritually true Homeland. An attempt is made to determine the essence of this concept give a brief description to its main characteristics. This substantiates the novelty of this study. The author concludes that the image of the venerable old man Sergius of Radonezh resembled the image Rus’ itself, which conveyed modesty, humbleness, purity and lightness, braveness and frankness, departure from rebel and extremes, humility and meekness, communication with God, love for the father’s house and parents, inner beauty and outward humbleness, sincere faith. All of these features are inherent to the Russian soul. Although it is not easy to discern such natural spiritual wealth in oneself, it will point the right path and lead to true sanctity that was achieved by the Venerable Sergius of Radonezh and described in the book of B. K. Zaitsev.