Charles Ellicott Commentary Mark 9:21

"And he asked his father, How long time is it since this hath come unto him? And he said, From a child." — Mark 9:21 (ASV)

And he asked his father.—The question, asked as if to strongly emphasize the chronic and therefore seemingly hopeless character of the possession, is unique to this Gospel, as is the detailed account of his frequently falling into the fire and into the waters.