So the passage was the one after the Transfiguration and after Jesus came down from his vacation and had to go right to work to heal a boy from his demon because his disciples could not do it.
30 They went on from there and passed through Galilee. And he did not want anyone to know, 31 for he was teaching his disciples, saying to them, “The Son of Man is going to be delivered into the hands of men, and they will kill him. And when he is killed, after three days he will rise.” 32 But they did not understand the saying, and were afraid to ask him.
Is anyone experiencing déjà vu? What happened the last time Jesus talked about his death?
8:32-33 -- Last time Peter tried to rebuke him. Nobody wanted to be called Satan this time, so they just kept their mouths shut. But did they get it?
So, they did not get it, and Jesus in his mercy does not let them stay confused. These guys thought they had power to exercise demons and heal people all on their own. Jesus first told them what defines his greatness, his death and resurrection, and how they can at least try to be that great.
Matthew Henry says, "Nothing could be more contrary to the two great laws of Christ's kingdom, lessons of his school, and instructions of his example, which are humility and love, than desiring preferment in the world, and disputing about it."
So he called a child. Now, when church people think of children, they think of these cute, innocent little people who are so precious. In Galilee, people saw children differently. To them, they were annoying and rude and dirty and basically in the way.
So what is Jesus trying to say with this child? To be great, you have to serve the annoying, rude, and dirty people who are in your way. You've got to be kind to people and care for their needs even when they reply by slapping you in the face. You must pray for them, even when they stop talking to you.
To be great means you have to get your hands dirty and hang out with people who aren't so beautiful. And only through God's grace can you even have power to turn the other cheek.
So Jesus, who really is the greatest, first shows that he's supposed to die a humiliating death for a world of people who are his enemies.
Second, he showed them the kind of people they need to serve.
To complete the trifecta, John finally confesses that they stopped a man from helping to exercise a demon because he wasn't one of them. Now think, would he have the power to cast out a demon had Jesus not called him? Unelect people can fake miracles, but they cannot cast out demons. This was clearly a follower of Jesus, but possibly not trained like the Apostles. Jesus takes their ego down a notch and shows them that they aren't the only servants for Jesus, not the ones in his elite club. God likes all his chosen people the same, and if someone is not against Christ, then he is for Christ. And we must both serve him and let him serve with us.