Then the disciples came to Jesus in private and asked, “Why couldn’t we drive [the demon] out?”
He replied, “Because you have so little faith. I tell you the truth, if you have faith as small as a mustard seed, you can say to this mountain, ‘Move from here to there’ and it will move. Nothing will be impossible for you.”
Faith IS small. We shouldn’t compare ours against His. The several times Jesus uses a mustard seed as a comparison for faith, he demonstrates that faith always starts small. But it will grow if you nurture it. And more importantly, no matter how small our faith may be, it will work its way into the hearts of those around us as long as we don’t make efforts to supress it.
All of us have seen sidewalks, driveways, streets, and even foundations of homes driven skyward as the result of trees whose roots have grown over the years. Instead of those roots driving deep into the soil to avoid the resistance of the thick concrete above it, it seeks out the moistest and most fertile soil: that soil that lies just beneath the surface.
And so those roots make the unconscious decision to grow, against all force, and enlarge themselves until everything around them is overwhelmed. And this is marvelous, because even if you cut down the tree, the roots and the upturned soil remain right where they are as a constant and visual reminder of just how awesome they were. Even in death, the roots have purpose.
So when Jesus talks of small faith, it’s only to indicate that faith is a seed. When planted and nurtured, the roots of the resulting tree can move mountains.
Interestingly, the mustard is of the family cruciferae. These plants have “four” petals/leaves arranged in a “cross.” Not a likely coincidence that Jesus used this particular plant for his parables.