John Calvin Commentary John 10:21

"Others said, These are not the sayings of one possessed with a demon. Can a demon open the eyes of the blind?" — John 10:21 (ASV)

These are not the words of a demoniac. It is as if they demanded that people should judge from the fact itself; for the truth, as we have said, is strong enough to maintain itself. And this is the only protection of our faith, that wicked people will never be able to hinder the power and wisdom of God, and his goodness also, from shining in the Gospel.