Be holy, for I am holy, the Lord your God (Lev. 19, 2) - this is the commandment of the Old Testament, especially since it is obligatory for us living already in the time of new grace. Indeed, likening your Lord is the natural path of every believing soul who loves God and seeks to conquer the sin living in it. However, evil sometimes seems omnipotent, and holiness is unattainable and accessible only to selected people who have reached perfection in spiritual life - saints. Whether it is possible to observe the commandment of holiness in the modern world is described in this book.