So they said to him, “Then how were your eyes opened?”
Such a wonderful event as the giving of sight to a man born blind could not but be the talk of the town, and many heeded it no more than they do other town-talk, that is but nine days' wonder; but here we are told what the neighbours said of it, for the confirmation of the matter of fact.
Commenting on John 9:8-12
Therefore said they unto him,.... When the case was clear, and it was out of question that he was the man: how were thine eyes opened? or made to see: they might well ask this question, since such a thing was never known before, that one born blind received his sight; and as great a miracle it is in grace, and as great a mystery...
Therefore said they unto him, How were thine eyes opened? (c) This is a Hebrew idiom, for they call a man's eyes shut when they cannot receive any light: and therefore blind men who are made to see are said to have their eyes opened.