8 “The neighbors therefore, and those who saw him previously, for he was a beggar, said, Is not this he who sat and begged? Some said, It is he: others, No; but he is like him.” The opening of his eyes had altered his countenance. “He said, I am he.” His voice utters its gratitude, that it might not be condemned as ungrateful. “Therefore said they unto him, How were your eyes opened? He answered, The man who is called Jesus made clay, and anointed my eyes, and said unto me, Go to the pool of Siloam, and wash: and I went and washed, and saw.” See, he has become the herald of grace; see, he preaches the gospel; endowed with sight, he becomes a confessor. That blind man makes confession, and the heart of the wicked was troubled; for they had not in their heart what he had now in his countenance. “They said to him, Where is he who has opened your eyes? He said, I know not.” In these words the man's own soul was like that of one only as yet anointed, but not yet seeing. Let us so put it, brethren, as if he had that anointing in his soul. He preaches, and knows not the Being whom he preaches.
Source: Tractates on the Gospel of John (New Advent)