Purity of heart means that every desire is for the same thing: God. Does this imply that other loves are wrong, or other goods illusory? No. The Christian view has never been a traditionally stoic one; we are never meant to deny or totally overcome our passions and desires. Instead, purity of heart refers to that joyful state of being in which we can freely love the good things of life while never losing sight of our North Star.
Achieving purity of heart, however, can be the work of a lifetime. Along the way, we are still apt to mistake the strong desire to feel that we are good for the state of actually being good. Whatever bolsters our sense of rightness or competence or giftedness or popularity can easily become part of the evidence we so desperately seek.
Thomas Merton’s spiritual autobiography, The Seven Storey Mountain, offers a classic example of the struggle it can be to sort out the difference. Though Merton honestly longed for purity of heart, he never knew for sure what was driving him. Before his conversion to Catholicism in his twenties, he’d already attracted the attention of the New York literary scene. Once he entered the Trappist monastery of Gethsemane to become a monk, he was worried that continuing to write would draw him back into his old longing for artistic acclaim. Yet he had an important story to tell—the story of a young man in the sophisticated twentieth century once again discovering the ancient Christian path. So he wrote his autobiography, which quickly became a bestseller and inspired a whole new generation to enter monastic life.
Merton did not doubt that God was using his gift; what continued to weigh on him the more famous he became was whether he himself was acting out of pure motives or was still being secretly driven by that old vainglory. Neither his fame as a writer nor his growing influence as a spiritual mentor could settle the issue for him. Eventually he realized that it was being faithful to the anonymous, daily discipline of monastic life that held the best possibility of purifying his heart. For being faithful to his practice meant making thousands of small decisions to continue putting God first in his life. The moment he allowed himself to be distracted by other things, no matter how worthy or good, he started to lose his bearings.
As in David Bella’s environmental model, our choices for lesser goods—for example, competence in our chosen field, social approval, an unimpeachable reputation, a happy family life, even peaceful relationships with others—can ultimately overwhelm the most fervent commitment to Christianity. The combined weight of these perfectly respectable decisions inexorably bends our spiritual trajectory. At the end of the day, we may be shocked to realize that we have spent most of our time and energy shoring up self-esteem, not living for Christ. What we devote ourselves to, in other words, ultimately defines us.