Charles Spurgeon Commentary John 9:14-15

"Now it was the sabbath on the day when Jesus made the clay, and opened his eyes. Again therefore the Pharisees also asked him how he received his sight. And he said unto them, He put clay upon mine eyes, and I washed, and I see." — John 9:14-15 (ASV)

And it was the Sabbath day when Jesus made the clay, and opened his eyes. Then again the Pharisees also asked him how he had received his sight.

That seemed to be the principal question with them; they always wanted to know the manner in which Christ's cures were performed.