Expositor's Bible Commentary Commentary John 9:18

"The Jews therefore did not believe concerning him, that he had been blind, and had received his sight, until they called the parents of him that had received his sight," — John 9:18 (ASV)

The evidence was still insufficient to remove the objections of “the Jews” (a phrase here synonymous with “the Pharisees”). They proceeded to query whether the man really had been born blind; for if he had not been blind from birth, the miracle could be disputed. They also interrogated his parents, who, fearing excommunication from the synagogue, evaded the issue by stating that their son was an adult capable of answering for himself.