When Jesus said, “If you have faith the size of a mustard seed, you will tell this mountain, ‘Move from here to there,’ and it will move, and nothing will be impossible for you,” most Christians take this as a criticism of their lack of faith. A mustard seed is about the smallest imaginable thing, so if your faith is smaller than that, it can’t be worth anything at all. If you haven’t moved a few mountains into new locations over the past month, your faith is probably pretty worthless. The only solution seems to be to grit your teeth and try harder to believe more impossible things.
But what if Jesus actually meant something quite different? What if he meant that it doesn’t really matter whether your faith is big or small? It’s not up to you; it’s up to God. God can still do great things through you if you let him, regardless of your faith level. Many people have had great faith in things which never happened, because their faith has been based on self-deception rather than on God’s will. Strength of conviction by itself is not enough. What you believe has to match up with what God is doing.
Maybe Jesus was saying that obedience to God combined with a tiny amount of faith is all that it takes. You don’t have to be a giant of the faith, and your mind can still be filled with doubts and feelings of inadequacy, so long as you don’t let them paralyse you and prevent you from listening to God and following where he is leading.