Every paragraph and every sentence of Journal of a Soul is steeped in a rich Catholic piety. There are the obvious external observances—the biblical quotations and the appeals to the Blessed Virgin Mary and to various saints—but these could easily be window dressing, done to be seen.
Rather, the heart of the Catholic nature of this work lies in the rich spiritual life behind the outward signs. For John XXIII, the saints are not merely names to be invoked, but role models who have a spiritual immediacy even though they lived in times and places remote from his present. He had a deep fascination with the lives and thoughts of such figures as Saint Francis de Sales, whom he regarded in many ways as a model for the ideal priest. Many of his entries consist of meditations on the examples of various saints and how he can best emulate them to improve himself spiritually.
Even the title, which was chosen long before the possibility that he might rise out of obscurity or that his writings might be published, is clearly drawn from L’Historie d’une âme (1898; Story of a Soul: The Autobiography of Saint Thérèse of Lisieux, 1951), the diary of spiritual reflections written by Saint Thérèse of Lisieux on the advice of her spiritual director. Although Saint Thérèse was a sheltered girl who went straight from her father’s household to a cloistered convent, never knowing the outside world, and John XXIII had to confront some of the worst evils of the twentieth century in the course of his duties, there are many similarities in their works, particularly in the tension between intense spiritual self-examination and joyous proclamation of God’s grace.