By Brett Robinson | Catholic News Service

How we come to know God? Faith and prayer for sure, but the physical world also provides material signs of his presence.

God's invisible power is made visible in the things of this world, but it's not always a beautiful sunset or breathtaking mountain view that showcases God's penchant for order and beauty. Sometimes it is in the most mundane, even trying, circumstances that his invisible workings are revealed.

When a family member was diagnosed with cancer several years ago, we began praying to St. Therese of Lisieux for her intercession. She was the patroness of our parish in Pittsburgh and our family had a long-standing devotion to her.

As soon as we finished the first novena, the doctor said the cancer treatment would involve a course of Bacillus Calmette-Guerin therapy or BCG, for short. BCG is a strain of the tuberculosis virus that is used to immunize people against tuberculosis. It also happens to be very effective at treating bladder cancer.

In all of the distress surrounding the diagnosis was a sign from the invisible God, astounding in its symmetry. The same virus that took St. Therese's life at age 24 was being used to treat the disease threatening our loved one.The source of our favorite saint's physical suffering was transformed into a source of healing. 

St. Therese's promise to continue helping those on earth once she reached heaven was realized once again in the very personal and particular circumstances of our family's struggle. 

There is a lot of valid concern today that the virtual and technological sphere of existence is numbing our ability to perceive the way that nature and grace conspire for good in our lives. If we fail to recognize the subtle workings of nature as signs of God's care for us, then it is harder to come to know him. Loving relationships require intimacy and attention to the very material things of the here and now.

It would be easy to say that the BCG treatment was a purely scientific achievement and to place our trust solely in the doctors, as if God's healing and saving power had been usurped by our own ingenuity. 

As Catholics, we know there is another level though. There are the physical facts and then there are the invisible realities that undergird them.

Perhaps it is the vocation of St. Therese's father, a watchmaker, whom she adored, that best illustrates how God's intervention in our lives can be witnessed in subtle ways in the material world.

St. Louis Martin's craft was making and repairing timepieces. The repairs he made would have been invisible to the clock's owner. A tiny gear wheel might be replaced or a spring adjusted. As a result, the clock would be renewed to fulfill its singular duty, to keep track of the passing of time.

To the hurried traveler checking the clock to make sure he makes the train, the inner workings of the clock are of little concern. He just needs to know the time. When the clock is working, we give little thought to its maker. 

But when it is not working, things become disordered. And unless attention is paid to the subtle and intricate inner workings of the clock, the disorder persists.

Knowing God, then, comes down to paying attention. Not just paying attention to what's happening on the surface of things but what is happening within.

Robinson is director of communications and Catholic media studies at the University of Notre Dame McGrath Institute for Church Life.