Since the world began was it not heard that any man opened the eyes of one that was born blind.

People's New Testament

9:30-33 Why herein is a marvellous thing. It was also a marvellous thing that one who was a blind beggar a few hours before should now expound theology to the very men that sat in Moses' seat (Mt 23:2) and show a better knowledge of the spirit of the Scriptures than the great ecclesiastics. Without the power of God no man could open the eyes of one born blind.

Matthew Henry's Concise Commentary

9:24-34 As Christ's mercies are most valued by those who have felt the want of them, that have been blind, and now see; so the most powerful and lasting affections to Christ, arise from actual knowledge of him. In the work of grace in the soul, though we cannot tell when, and how, and by what steps the blessed change was wrought, yet we may take the comfort, if we can say, through grace, Whereas I was blind, now I see. I did live a worldly, sensual life, but, thanks be to God, it is now otherwise with me, Eph 5:8. The unbelief of those who enjoy the means of knowledge and conviction, is indeed marvellous. All who have felt the power and grace of the Lord Jesus, wonder at the wilfulness of others who reject him. He argues strongly against them, not only that Jesus was not a sinner, but that he was of God. We may each of us know by this, whether we are of God or not. What do we? What do we for God? What do we for our souls? What do we more than others?