The aim of this article is to answer the question, “How Philaret Drozdov understood God’s holiness and human holiness and how both the ideas were displayed in his writings?” The research material constitutes selected homilies and a catechism. In the first place, the author discusses the definition of holiness and its understanding by the Orthodox Church with regard to the issue of deification. Also, he familiarizes the reader with the concept of holiness in its various aspects. Subsequently, the homilies and the catechism of Philaret Drozdov are analysed. The article shows the Moscow Metropolitan’s beliefs about the essence of human holiness as well as about the eschatological dimension of temporality and the pneumatological aspect of holiness, the issue of grace and a human seen as a vessel of God’s energy. The author proves that the Moscow Metropolitan continued in his works the traditions of the Church Fathers and creatively developed the most important assumptions of Orthodox anthropology and soteriology and, hence enriching Russian spiritual thought.