Jesus said that if we have the faith of a grain of mustard seed, we can do anything, including some really radical earthwork. Healing a terminal illness should be a breeze. Right?
Well, under those rules, yes, there should be miraculous cures right and left, along with the Mt. Everest Sailing Resort. I mean, we're people, and we can sure pack more faith into our personas than can a lil' ol' mustard seed, right?
But that doesn't happen. Mountains do not take a last landward bow before swimming. And doctors are still driving BMWs.
I don't doubt that there are miraculous cures - I saw a splenic tumor in a German Shepherd shrink from nearly a foot long to nothing.
It's just that there aren't very many. Few claimed, fewer verified - and verification is a fair test. I don't think Jesus would have shied away from it - indeed he invited people to see for themselves, and be convinced.
My thought is that when Jesus talked about the mustard seed, he was actually referring to a degree of faith that we can almost never achieve. The seed is 'all faith'; it doesn't doubt, because it's never been exposed to intellectual rigor (or rigor mortis, if you prefer). We, on the other hand, question everything. "I took it on faith" is often seen as a sign of almost hopeless naivete.
The power of faith grows exponentially with its purity, then? And the enormity of the seed's faith thus arises from its complete lack of adulteration. That is the goal that is nearly unreachable to us mortals.
Maybe it's the way it's supposed to be - mountains being tossed into the sea would give Lloyd's of London a headache, so Jesus set us a goal we could never reach.
But He never said, don't try.