Albert Barnes Commentary John 9:2

"And his disciples asked him, saying, Rabbi, who sinned, this man, or his parents, that he should be born blind?" — John 9:2 (ASV)

Master, who did sin? etc. It was a universal opinion among the Jews that calamities of all kinds were the effects of sin (see Barnes on Luke 13:1-4).

The case of this man, however, was that of one who was blind from his birth, and it was a question the disciples could not determine whether it was his fault or that of his parents.

Many of the Jews, as it appears from their writings (see Lightfoot), believed in the doctrine of the transmigration of souls. This doctrine held that the soul of a man, as a consequence of sin, might be compelled to pass into other bodies and be punished there.

They also believed that an infant might sin before it was born (see Lightfoot), and that, consequently, this blindness might have come upon the child.

It was also a doctrine with many that the crime of the parent might be the cause of deformity in the child, particularly the violation of the command in Leviticus 20:18.