Mark 9:14-29 tells the story of the healing of a boy with a spirit that 'makes him mute' and causes some sort of seizure or fit. When Jesus arrives on the scene, the crowd "were greatly amazed" — but why are they amazed before he heals the boy?

¹⁴And when they came to the disciples, they saw a great crowd around them, and scribes arguing with them. ¹⁵And immediately all the crowd, when they saw him, were greatly amazed and ran up to him and greeted him. ¹⁶And he asked them, “What are you arguing about with them?” ¹⁷And someone from the crowd answered him, “Teacher, I brought my son to you, for he has a spirit that makes him mute. ¹⁸And whenever it seizes him, it throws him down, and he foams and grinds his teeth and becomes rigid. So I asked your disciples to cast it out, and they were not able.” _ESV