Certainly this is wonderful. He indirectly reproves them for remaining unmoved by a miracle so illustrious, and for pretending that they did not know Christ's calling; as if he had said, that it was highly improper that such a testimony of Divine power should be held in no estimation, and that the calling of Christ, so proved and attested, should obtain no credit among them. And, in order to show more clearly their stupidity or malice, he magnifies the excellence of the miracle from this consideration, that, as far as the memory of men reaches, none was ever heard to say that such a thing was done by a man. Hence it follows that they are malicious and ungrateful, because they voluntarily shut their eyes on a manifest work of God. He infers from this, that Christ was sent by God, because he is endued with so great power of the Spirit of God, to procure credit for himself and for his doctrine.

A marvelous thing - This is wonderful and amazing.
Know not from whence he is - That you cannot perceive that he who has performed such a miracle must be from God.

Why herein is a marvellous thing - As if he had said, This is wonderful indeed! Is it possible that such persons as you are, whose business it is to distinguish good from evil, and who pretend to know a true from a false prophet, cannot decide in a case so plain? Has not the man opened my eyes? Is not the miracle known to all the town; and could any one do it who was not endued with the power of God?

The man answered and said unto them,.... Very appropriately and pertinently,
why herein is a marvellous thing; strange and unaccountable,
that ye know not from whence he is; that you learned doctors, men of sagacity and penetration, should not be able to discern that this man is of God, is a prophet sent by him, and that there should be any doubt from whence he comes, or from whom he has his commission:
and yet he hath opened mine eyes; which was so clearly and plainly the work of the Messiah, and to be done by him when he came, Isaiah 35:4.

The man answered, Herein is a marvellous thing, that ye know not from whence he is, and yet he hath opened mine eyes--He had no need to say another word; but waxing bolder in defense of his Benefactor, and his views brightening by the very courage which it demanded, he puts it to them how they could pretend inability to tell whether one who opened the eyes of a man born blind was "of God" or "a sinner"--from above or from beneath--and proceeds to argue the case with remarkable power. So irresistible was his argument that their rage burst forth in a speech of intense Pharisaism, "Thou wast altogether born in sins, and dost thou teach us?"--thou, a base-born, uneducated, impudent youth, teach us, the trained, constituted, recognized guides of the people in the things of God! Out upon thee!

Herein is a marvellous thing. It was also a "marvellous thing" that one who was a blind beggar a few hours before should now expound theology to the very men that "sat in Moses' seat" and show a better knowledge of the spirit of the Scriptures than the great ecclesiastics. Without the power of God no man could open the eyes of one born blind.

The man answered - Utterly illiterate as he was. And with what strength and clearness of reason! So had God opened the eyes of his understanding, as well as his bodily eyes. Why, herein is a marvellous thing, that ye - The teachers and guides of the people, should not know, that a man who has wrought a miracle, the like of which was never heard of before, must be from heaven, sent by God.