In Hidden Holiness, Michael Plekon challenges us to examine the concept of holiness. He argues that both Orthodox and Catholic churches understand saints to be individuals whose lives and deeds are unusual, extraordinary, or miraculous. Such a requirement for sainthood undermines, in his view, one of the basic messages of Christianity: that all people are called to holiness.

Instead of focusing on the ecclesiastical process of recognizing saints, Plekon explores a more ordinary and less noticeable “hidden” holiness, one founded on the calling of all to be prophets and...