You have heard that story in the gospel where we are told that the Lord Jesus, as he was passing by, caught sight of a man who had been blind from birth. Since the Lord did not overlook him, neither ought we to overlook this story of a man whom the Lord considered worthy of his attention. In particular we should notice the fact that he had been blind from birth. This is an important point.
There is, indeed, a kind of blindness, usually brought on by serious illness, which obscures one’s vision, but which can be cured, given time; and there is another sort of blindness, caused by cataract, that can be remedied by a surgeon: he can remove the cause and so the blindness is dispelled. Draw your own conclusion: this man, who was actually born blind, was not cured by surgical skill, but by the power of God. When nature is defective, the Creator, who is the author of nature, has the power to restore it. This is why Jesus also said “As long as I am in the world, I am the light of the world,” meaning: all who are blind are able to see, so long as I am the light they are looking for. Come, then, and receive the light, so that you may be able to see.
What is he trying to tell us, he who brought human beings back to life, who restored them to health by a word of command, who said to a corpse. “Come out!” and Lazarus came out from the tomb; who said to a paralytic. “Arise and pick up your stretcher,” and the sick man rose and picked up the very bed on which he used to be carried as a helpless cripple?
Again, I ask you, what is he trying to convey to us by spitting on the ground, mixing his spittle with clay and putting it on the eyes of a blind man, saying: “Go and wash yourself in the pool of Siloam (a name that means ‘sent’)”? What is the meaning of the Lord’s action in this? Surely one of great significance, since the person whom Jesus touches receives more than just his sight.
In one instant we see both the power of his divinity and the strength of his holiness. As the divine light, he touched this man and enlightened him; as priest, by an action symbolizing baptism he wrought in him his work of redemption. The only reason for his mixing clay with the spittle and smearing it on the eyes of the blind man was to remind you that he who restored the man to health by anointing his eyes with clay is the very one who fashioned the first man out of clay, and that this clay that is our flesh can receive the light of eternal life through the sacrament of baptism.
You, too, should come to Siloam, that is, to him who was sent by the Father (as he says in the gospel. “My teaching is not my own, it comes from him who sent me).” Let Christ wash you and you will then see. Come and be baptized, it is time; come quickly, and you too will be able to say, “I went and washed;” you will be able to say, “I was blind, and now I can see,” and as the blind man said when his eyes began to receive the light. “The night is almost over and the day is at hand.”
St Ambrose of Milan