Charles Spurgeon Commentary Mark 9:13

"But I say unto you, that Elijah is come, and they have also done unto him whatsoever they would, even as it is written of him." — Mark 9:13 (ASV)

And they have done unto him whatsoever they listed, as it is written of him.

It is rather singular that the disciples should begin to ask about the scribes, for this was, as it were, a sort of warning note for a battle into which they were about to plunge. They talked about the scribes, but the scribes were down below in conflict with the rest of the apostolic brotherhood, and now, while they are talking about them, they find themselves immediately in their presence.