John Calvin Commentary John 9:25

"He therefore answered, Whether he is a sinner, I know not: one thing I know, that, whereas I was blind, now I see." — John 9:25 (ASV)

Whether he be a sinner, I know not. The blind man does not appear to have been at all prevented by fear from giving a sincere testimony. For there is no reason to believe that he had any doubts about Christ, as his words seem to imply; rather, I think that he spoke ironically, in order to wound them more deeply.

He had already confessed that Christ was a Prophet (John 9:17). Perceiving that he gains nothing by doing so, he suspends his judgment about the person and brings forward the fact itself, so that, while he makes this admission in their favor, he is not free from ridiculing them.