I recently learned that all the cells in all the muscles in the human body are destroyed, hauled off, then rebuilt about every four months. Ditto with all the blood cells every three months, all the bone cells every couple of years. Who knew?

When we stress muscles with exercise, special wrecking-crew cells get a stronger-than-usual signal to come in and start tearing things down and cleaning things out. Rest after exercise cues another crew of cells to start building things back up again, just a little stronger than before. Without exercise, old cells don’t get taken down and recreated as efficiently; muscles and bones are rebuilt slightly weaker than they were, according to Chris Crowley and Henry S. Lodge, M.D., authors of "Younger Next Year."

This information gives me a lot of incentive to hit the streets.

It also gives new credibility to the notion that adversity might even be good for me. It makes me wonder if I’m using challenges, stress or threats to tear down old notions of who I am and what I believe, replacing them with something more accurate, strong and flexible.

I think of a friend who, with cause, concluded as a child that she could only stay safe through constant vigilance. People could not always be trusted. Ditto with God. As an adult that worldview often left her anxious, suspicious and grasping for faith. She wanted to relax and trust in God’s care. After all, sometimes things worked out fine. But sooner or later — usually sooner — they didn’t again. Was she not yet righteous enough to deserve more protection? Was she creating a self-fulfilling prophecy?

I will long remember the moment in the movie "17 Miracles" when someone who looks like a mountain man comes to a woman who has roamed away from her Mormon pioneer handcart company to search for fuel. He appears from nowhere and asks urgently how the company is doing. She clearly can’t figure out who this man is or where he came from, but she reports, "We are starving. We are dying. We are desperate."

His concern is evident. He thinks a moment. He wonders aloud if he might help a little. The question does not seem to be whether he is able to help, willing to help, or has the concern and compassion to help. For some reason the question seems to be whether he is allowed to help. Apparently permission is granted: He miraculously provides dried meat for her to take back and distribute, saving many lives. When she turns to thank him he has disappeared, along with the cave from which he produced the food. True story, it is claimed.

This is the message I got: God is absolutely aware, compassionate, concerned — and from time to time he sends some messenger or miracle as evidence of that love. But he does not pull us out of the game we came here to play. He respects and loves and trusts us enough to let us see it through, even when we are sure we are losing, even when we cannot for the life of us remember why we chose to play or what position we trained for. He remembers. He is true to his promise to let us have the experience we apparently signed up for: tearing down, rebuilding stronger.

Sometimes an experience tears us down so far we feel like there is no physical or spiritual muscle left to rebuild from. But he is the resurrection and the life and the God we can come to know “in our extremities.” He can be trusted, not because he will keep us safe but because he will save us. We are loved enough and he is good enough, and we can take that to the bank. The victory is his, but the spiritual muscle will be ours, forever.

Wendy Ulrich, PhD, MBA, psychologist, author and founder of Sixteen Stones Center for Growth (sixteenstones.net), most recently co-authored the New York Times bestseller "The Why of Work."

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