“Jesus heard that they had cast him out; and when he had found him, he said unto him, Dost thou believe on the Son of God?”
John 9:35 — Greek Interlinear
Church Fathers on John 9:35
Those who suffer for the truth’s sake, and confession of Christ, come to greatest honor; as we see in the instance of the blind man. For the Jews cast him out of the temple, and the Lord of the temple found him; and received him as the judge cloth the wrestler after his labors, and crowned him: Jesus heard that they had cast him out; and when He had found him, He said to him, Do you believe in the Son of God? The Evangelist makes it plain that Jesus came in order to say this…
If any mere confession whatsoever of Christ were the perfection of faith, it would have been said, Do you believe in Christ? But inasmuch as all heretics would have had this name in their mouths, confessing Christ, and yet denying the Son, that which is two of Christ alone, is required of our faith, viz. that we should believe in the Son of God. But what avails it to believe on the Son of God as being a creature, when we are required to have faith in Christ, not as a creature…
This He says to remind him of his cure, which had given him the power to see. And observe, He that speaks is born of Mary, and the son is the Son of God, not two different Persons, according to the error of Nestorius: And it is He that talks with you.