Three disciples have just been on a mountain watching Jesus' face shine like the sun. The other nine are at the foot of it, failing in public at something they have done before. Jesus gave them authority over unclean spirits back in chapter 10, and they used it. Now a desperate father kneels in front of Jesus with a son whose seizures have thrown him into fire and water again and again. 16"I brought him to your disciples, and they could not heal him." Jesus rebukes the demon, and 18"the boy was healed instantly."
The authority Jesus gave them was never revoked or defective. Something had shifted between chapter 10 and this moment. Confidence in the gift had quietly taken the place of dependence on the giver. Authority handed to you once is not the same as faith exercised right now for this particular need.
The disciples ask him privately, 19"Why could we not cast it out?" His answer is short. Because of your little faith. Little faith is still faith, and these are men who had cast out demons before. It describes faith gone thin, watered down by overconfidence or distraction or forgetting whose power was doing the work all along.
Then comes the saying about the mustard seed: 20"if you have faith like a grain of mustard seed." It is easy to hear it as a promise that enough faith, stacked high enough, unlocks unlimited power. But a mustard seed was proverbially the smallest seed anyone planted. Jesus is saying that faith, however small, placed in the God who is able, matters far more than any large quantity of faith placed in itself. What the seed is planted in was always the point.
That means the disciples' failure was not like running short of money. God's power flows through whatever faith is present, tiny or great, as long as it is fixed on him and not on the gift already given, the method already learned, or the outcome already assumed.
Then, almost without transition, Jesus tells them for the second time that he is going to die. 23"They will kill him, and he will be raised on the third day." This time no one argues, as Peter did the first time. 23"And they were greatly distressed." The grief has landed fully. Whatever they do not yet understand about the resurrection, they understand the cross. Two failures sit side by side in this passage, a failed exorcism and a struggle to accept the cross, and both come from the same unfinished place. Their faith was there, and it had not yet grown enough to reach all the way around who Jesus is and what he came to do.
Ask what gift, method, or past success you are leaning on in place of him. Bring the smallest honest trust you have, aimed straight at the one who can do what you cannot.
Prayer
Father, we have made this mistake, letting confidence in a gift or a method stand in for trust in you until need exposed the gap. Thank you that what matters is the one our faith is planted in. Grow in us faith, however small it starts, fixed on you and not on what we have already learned. In Jesus' name, amen.