Analyzing her deeds and achievements, John Paul II asked: "Where did Mother Teresa find the strength and perseverance to place herself completely at the service of others? She found it in prayer and in the silent contemplation of Jesus Christ, his Holy Face, his Sacred Heart." Privately, Mother Teresa experienced doubts and struggles over her religious beliefs which lasted nearly fifty years until the end of her life, during which "she felt no presence of God whatsoever", "neither in her heart or in the eucharist" as put by her postulator Rev. Brian Kolodiejchuk. Mother Teresa expressed grave doubts about God's existence and pain over her lack of faith:
Where is my faith? Even deep down ... there is nothing but emptiness and darkness ... If there be God—please forgive me. When I try to raise my thoughts to Heaven, there is such convicting emptiness that those very thoughts return like sharp knives and hurt my very soul ... How painful is this unknown pain—I have no Faith. Repulsed, empty, no faith, no love, no zeal, ... What do I labor for? If there be no God, there can be no soul. If there be no soul then, Jesus, You also are not true.
With reference to the above words, the Rev. Brian Kolodiejchuk, her postulator (the official responsible for gathering the evidence for her sanctification) indicated there was a risk that some might misinterpret her meaning, but her faith that God was working through her remained undiminished, and that while she pined for the lost sentiment of closeness with God, she did not question his existence. Many other saints had similar experiences of spiritual dryness, or what Catholics believe to be spiritual tests ("passive purifications"), such as Mother Teresa's namesake, St. Therese of Lisieux, who called it a "night of nothingness." Contrary to the mistaken belief by some that the doubts she expressed would be an impediment to canonization, just the opposite is true; it is very consistent with the experience of canonized mystics.
Mother Teresa described, after ten years of doubt, a short period of renewed faith. At the time of the death of Pope Pius XII in the fall of 1958, praying for him at a requiem mass, she said she had been relieved of "the long darkness: that strange suffering." However, five weeks later, she described returning to her difficulties in believing.
Mother Teresa wrote many letters to her confessors and superiors over a 66-year period. She had asked that her letters be destroyed, concerned that "people will think more of me—less of Jesus." However, despite this request, the correspondences have been compiled in Mother Teresa: Come Be My Light (Doubleday). In one publicly released letter to a spiritual confidant, the Rev. Michael van der Peet, she wrote, "Jesus has a very special love for you. [But] as for me, the silence and the emptiness is so great, that I look and do not see,—Listen and do not hear—the tongue moves [in prayer] but does not speak ... I want you to pray for me—that I let Him have [a] free hand."
Many news outlets have referred to Mother Teresa's writings as an indication of a "crisis of faith." Some critics of Mother Teresa, such as Christopher Hitchens, view her writings as evidence that her public image was created primarily for publicity despite her personal beliefs and actions. Hitchens writes, "So, which is the more striking: that the faithful should bravely confront the fact that one of their heroines all but lost her own faith, or that the Church should have gone on deploying, as an icon of favorable publicity, a confused old lady who it knew had for all practical purposes ceased to believe?" However, others such as Brian Kolodiejchuk, Come Be My Light's editor, draw comparisons to the 16th century mystic St. John of the Cross, who coined the term the "dark night of the soul" to describe a particular stage in the growth of some spiritual masters. The Vatican has indicated that the letters would not affect her path to sainthood. In fact, the book is edited by the Rev. Brian Kolodiejchuk, her postulator.
In his first encyclical Deus Caritas Est, Benedict XVI mentioned Teresa of Calcutta three times and he also used her life to clarify one of his main points of the encyclical. "In the example of Blessed Teresa of Calcutta we have a clear illustration of the fact that time devoted to God in prayer not only does not detract from effective and loving service to our neighbour but is in fact the inexhaustible source of that service." Mother Teresa specified that "It is only by mental prayer and spiritual reading that we can cultivate the gift of prayer."
Although there was no direct connection between Mother Teresa's order and the Franciscan orders, she was known as a great admirer of St. Francis of Assisi. Accordingly, her influence and life show influences of Franciscan spirituality. The Sisters of Charity recite the peace prayer of St. Francis every morning during thanksgiving after Communion and many of the vows and emphasis of her ministry are similar. St. Francis emphasized poverty, chastity, obedience and submission to Christ. He also devoted much of his own life to service of the poor, especially lepers in the area where he lived.
