Pseudo-Jerome — as excerpted in the Catena Aurea on Mark 9:14-29

“Now it was the people, and not the disciples, who on seeing Him were amazed and feared, for there is no fear in love; fear belongs to servants, amazement to fools. It goes on: And he asked them, What question ye with them. Why does the Lord put this question? That confession may produce salvation, and the murmuring of our hearts may be appeased by religious words.”