To this they replied,”You were steeped in sin at birth; how dare you lecture us!” And they threw him out.
You know that you have won the argument when your opponent gets so spittin’ mad that they resort to calling you names and throwing you out. It is instructive to read between the lines here and see how the man who was formerly blind responds.
So far in this story, Jesus happened by a man blind from birth. When asked why the man had been born blind Jesus replied, “…so that the works of God might be displayed in him.” Then, he healed the man. Immediately people started arguing about whether or not it was the same man. After all, it is not natural for a person who has been blind to gain their sight. The argument is continued in front of the Pharisees who, not believing the man either, demand to hear it from his parents.
“Is this your son?” they asked. “Is this the one you say was born blind? How is it that now he can see?” “We know he is our son,” the parents answered, “and we know he was born blind. But how he can see now, or who opened his eyes, we don’t know. Ask him. He is of age; he will speak for himself.” His parents said this because they were afraid of the Jewish leaders, who already had decided that anyone who acknowledged that Jesus was the Messiah would be put out of the synagogue. That was why his parents said, “He is of age; ask him.”
John 9: 19-23
I give the parents full marks for caution. They literally did not “know” what had happened to their son. They answered as if they were in a court of law. (This was before Perry Mason was on TV, too!) They were wise to do this as in fact, they were in a kind of court.