Charles Ellicott Commentary John 9:30

"The man answered and said unto them, Why, herein is the marvel, that ye know not whence he is, and [yet] he opened mine eyes." — John 9:30 (ASV)

Why herein is a marvellous thing.—Several of the better manuscripts read more emphatically, the marvellous thing. He again puts two contradictory positions—their assertion that they did not know by what authority Jesus did these things (from where He was), and the evident fact that He had opened his eyes. He cannot reconcile their statement with what he knows to be true, and he states his wonder in the strongest form.

That ye know not from whence he is—that is, you whose business it is to know, you who claim for yourselves a special knowledge of all such questions, and whose duty it is to inquire into the authority of any one who asserts that he is a teacher or a prophet. (Compare Note on John 1:24.)