In the short story Father Sergius, Tolstoi tells about the guards officer Kasatskii who renounces his military career, enters a monastery, then leaves it again in order to become hermit. Finally, he ends up as a simple vagabond. The drama unfolds on the inner plane, but is reflected in three incidents when Kasatskii alias Father Sergius suddenly breaks away from his former life and finds new meaning in an existence that coincides with four traditional forms of Orthodox piety; monasticism, eldership, holy wandering. He ends up in holy foolishness, which combines elements of them all, as a life in the world, but not of the world. The life of Kasatskii alias Father Sergius is a circular motion. He starts in the world, withdraws from it, and finally returns to it. However, he has not come back to the starting point, for he is now equipped with new insights about God and life. These varieties of piety prove to be, with the words of Søren Kierkegaard, "stages on the path of life," hierarchically arranged. Despite the abrupt breaks between them, they must be understood as parts of a developmental process, all contributing to a cumulative maturation.

The English expression “holy fool” is a somewhat misleading translation of the Russian phenomenon of iurodstvo. The word “fool” suggests that antirationalism was an essential element of this traditional folk spirituality. However, in the Orthodox understanding, asceticism, in the shape of struggle against the passions and a strive for moral perfection, was a far more important aspect of this piety. This corresponds also to Tolstoi’s understanding of “holy foolishness.” The holy fools preached their moral and social message indirectly, in a hidden and symbolic way, through actions and not by proclamations. They broke the social norms of society, and thereby incurred people’s contempt and derision. The fools renounced not only the security of home, hearth and material security but even cleanliness. In his debut novel Childhood, Tolstoi portrayed with great sympathy the holy fool Grisha, modeled on several fools who visited their home. To Tolstoi the outer form of holy foolishness, however, was far less important than the inner attitude of breaking with the world. In his diaries, he several times referred to holy fool as an example of holiness to emulate, but never explicitly identified with it. Many of his contemporaries, however, did exactly that, usually to scorn him.