People talk about having a "spring in their step." Now you can buy one from Nike. The giant shoe company, after 16 years of research, just released sneakers called Shox, which actually have four strong springs in the heel. When you press down, the brightly colored springs, made of high-density foam, push back up. You jump, and they assist. Shox are intended to help you run faster and jump higher than you could on your own.

Bruce Kilgore, director of advanced research and development at Nike, describes what happened when runners tested out a prototype: "Smiles . . . would break out on people's faces as they were running."

Christians, too, have an inner resilience that is not their own. It's the power of the Spirit. With that power, we can do things we could never do on our own.