What are we to make of Mother Teresa's letters, collected in a new volume called " Mother Teresa: Come Be My Light," which reveal decades of spiritual depression, loneliness and doubt? Should this console us or disturb us?

The pious answer is that these sentiments humanize the distant saint, showing that even the great have their struggles. But this underestimates the rawness and intensity of the letters themselves, which are in fact disturbing.

Mother Teresa in 1995.

In the 1950s she wrote: "Lord, my God, who am I that You should forsake me? The child of your love -- and now become as the most hated one -- the one You have thrown away as unwanted -- unloved. I call, I cling, I want -- and there is no One to answer -- no One on Whom I can cling -- no, No One. Alone . . . I am told God loves me -- and yet the reality of darkness & coldness & emptiness is so great that nothing touches my soul."

This is clearly not an intellectual skepticism, a normal crisis of faith. It is a profound sense of abandonment. In September of 1946, then-Sister Teresa had heard a voice calling her to serve the poorest of the poor -- what she interpreted as the voice of Jesus, asking her: "Wilt thou refuse?" But not long after this mystical encounter . . . nothing. In the long obedience that followed, there were no more spiritual consolations, no rewards of divine closeness, just interior darkness and silence. "I long for God," she wrote, but find "longing and no love." Having tasted the divine -- like a single day with a vanished lover -- God's absence seems to her beyond the tortures of nihilism. Only a believer would feel this divine departure so deeply. Martin Buber called this kind of experience the "eclipse of God" -- and it was made more terrible by Mother Teresa's vivid memory of the sun.

All of this was shocking to many who knew her, because she was constantly cheerful and smiling -- a manner she called "the cloak by which I cover the emptiness & misery." Rather than being hypocritical, this seems to have been peasant toughness. She often told others: "Pull yourself up," "Just be cheerful" and "Keep smiling" -- advice she followed herself. Such cheerfulness was not false but willed. And there is a kind of courage in losing hope without losing heart.

Eventually, on the evidence of the letters, Mother Teresa made peace with her darkness, identifying her own anguish with the suffering of her Savior and the suffering of the poor. "Now it does not really seem so hard," she eventually concluded. But she never regained the subjective religious experiences of her youth. "If ever I become a saint," she said, "I will surely be one of 'darkness.' "

There are lessons in this complicated spiritual life -- that holiness has more to do with obedience than spiritual feelings; that faith can coexist with suffering and doubt; that sainthood can be harsher and more difficult than we imagine.

But Mother Teresa's sense of abandonment raises a deeper issue. Assuming, for a moment, that she was not self-deluded in her calling, what kind of God would set such a difficult path -- ministering to lepers and outcasts for a lifetime -- and then withdraw his presence? Mother Teresa herself seemed to struggle with this unfairness: "What are you doing My God to one so small?"

There is no easy answer here, but the question is central to the Christian faith. Other noble religious traditions promise serenity, detachment from striving and release from the suffering of the world. Christianity, in contrast, teaches that grace is found in the worst of that suffering, and through a figure who despairs of God's presence in his parting words. This anguish is not convenient -- "Why hast Thou forsaken me?" is hardly the best religious marketing slogan. But for millennia this abandonment has offered hope that God might somehow be present even in shame, loneliness and betrayal, even on the descending path of depression, even in the soul's hardness and doubt, even in the silence of God himself -- and that all these things may be the preface to glory.

Through her pain-filled letters, Mother Teresa offers this assurance: Even when all we have to offer is ashes, and all we feel is emptiness, something beautiful may come of it in the end. But her decades of lonely sorrow are not an easy source of comfort. And Graham Greene might have been speaking of this abandoned mystic when he wrote: "You can't conceive, my child, nor can I or anyone the . . . appalling . . . strangeness of the mercy of God."

michaelgerson@cfr.org