1 We have heard the lesson of the Holy Gospel which we are in the habit of hearing; but it is a good thing to be reminded: good to refresh the memory from the lethargy of forgetfulness. And in fact this very old lesson has given us as much pleasure as if it were new. Christ gave sight to one blind from his birth; why do we marvel? Christ is the Saviour; by an act of mercy He made up that which He had not given in the womb. Now when He gave that man no eyes, it was no mistake of His surely; but a delay with a view to a miracle.
You are saying, it may be, “Whence do you know this?” From Himself I have heard it; He just now said it; we heard it all together. For when His disciples asked Him, and said, “Lord, who did sin, this man or his parents, that he was born blind?” What answer He made, you heard, as did I. “Neither has this man sinned, nor his parents, but that the works of God should be made manifest in him.” Lo then wherefore it was that He delayed when He gave him no eyes. He did not give what He could give, He did not give what He knew He should give, when need was.
Yet do not suppose, Brethren, that this man's parents had no sin, or that he himself had not, when he was born, contracted original sin, for the remission of which sin infants are baptized unto remission of sins. But that blindness was not because of his parents' sin, nor because of his own sin; “but that the works of God should be made manifest in him.” For we all when we were born contracted original sin: and yet we were not born blind. However enquire carefully, And we were born blind. For who was not born blind? Blind, that is, in heart. But the Lord Jesus, for that He had created both, cured both.
Source: Sermons on Selected Lessons of the New Testament (New Advent)