"Jesus has a very special love for you. As for me, the silence and the emptiness is so great that I look and do not see, listen and do not hear," Mother Teresa to the Rev. Michael Van Der Peet, September 1979.
"Where is my faith? Even deep down … there is nothing but emptiness and darkness. ... If there be God please forgive me... Such deep longing for God ... 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," - Mother Teresa in her correspondence.
"The 16th century writer Michel de Montaigne lived in a world of religious war, just as we do. And he understood, as we must, that complete religious certainty is, in fact, the real blasphemy. As he put it, "We cannot worthily conceive the grandeur of those sublime and divine promises, if we can conceive them at all; to imagine them worthily, we must imagine them unimaginable, ineffable and incomprehensible, and completely different from those of our miserable experience. 'Eye cannot see,' says St. Paul, 'neither can it have entered into the heart of man, the happiness which God hath prepared for them that love him.'"
In that type of faith, doubt is not a threat. If we have never doubted, how can we say we have really believed? True belief is not about blind submission. It is about open-eyed acceptance, and acceptance requires persistent distance from the truth, and that distance is doubt. Doubt, in other words, can feed faith, rather than destroy it. And it forces us, even while believing, to recognize our fundamental duty with respect to God's truth: humility. We do not know. Which is why we believe," - The Conservative Soul.