Luke 9:39 Meaning

37And it came to pass, that on the next day, when they were come down from the hill, much people met him.

38And, behold, a man of the company cried out, saying, Master, I beseech thee, look upon my son: for he is mine only child.

39And, lo, a spirit taketh him, and he suddenly crieth out; and it teareth him that he foameth again, and bruising him hardly departeth from him.

40And I besought thy disciples to cast him out; and they could not.

41And Jesus answering said, O faithless and perverse generation, how long shall I be with you, and suffer you? Bring thy son hither.