A Marvelous Faith

What would make Jesus say, "Wow"? In Luke 7:1-17 we are told Jesus marveled at someone's faith. A centurion had a terminally sick servant. Some Jewish elders begged Jesus to come and heal the servant because the centurion had done good things for Israel. In other words, they believe he is worthy (vs. 4). But the centurion disagrees. He tells Jesus not to come because he isn't worthy (vs. 6). Who is right? What does this story teach us about the nature of true faith?