Matthew 21 describes how Jesus caused a fig tree to shrivel up. When his disciples asked him how he had done that, he replied: “I can guarantee that if you have faith and don’t doubt, you will not only do what was done to the fig tree, but if you ordered this mountain, ‘Rise up and fall into the sea,’ it would happen. You will receive whatever you ask in prayer, if you believe.”
This is a difficult passage to understand. I’ve met plenty of people who claimed to have the faith to work miracles, but I have never actually seen anyone use faith to cast a mountain into the sea. And why would God want people to be using faith to hurl mountains around anyway? What precisely is faith, and how does it work?
It seems to me that there is a difference between faith and hope. Hope is where you want something to happen but God hasn’t promised it. Faith is where God has promised something so you can rely on him to do it. People pray all the time for healing, and God does sometimes provide miraculous healing, but in the end everyone dies, no matter how much people have prayed for their recovery. God hasn’t promised us a healthy and pain-free life on this earth, so prayer for healing is in the “hope” category rather than the “faith” category.
When Jesus was talking about moving mountains with faith, he wasn’t talking about us screwing up our faces and hoping hard enough for some miracle of our own choosing to happen. He was talking about how we can rely on the promises he has already made to see his kingdom come in miraculous ways.