Mark 9:15 Meaning

13But I say unto you, That Elias is indeed come, and they have done unto him whatsoever they listed, as it is written of him.

14And when he came to his disciples, he saw a great multitude about them, and the scribes questioning with them.

15And straightway all the people, when they beheld him, were greatly amazed, and running to him saluted him.

16And he asked the scribes, What question ye with them?

17And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit;