It depends on what you mean by incarnation. If you mean by incarnation that he existed in the flesh, as a man, then there was a man sent by God, and, a man called Jesus made clay and washed in the pool of Siloam. Also, testimony is not heard by man. Thus, if John was a man sent to come to testify about the existence of Jesus, then he could not have heard his own testimony if he remained as a man. There are numerous references to man in the Gospel, but when he made clay, then he used earth, material, and water, mind or conscious,.to cover his eyes. Thus the Mind of God has been deluded, covered, made blind to the immaterial existence of Whom He is, because he had from the beginning always been but had become blind because,.precisely, there was a purpose for having the truth concealed by our identification with the consciousmaterial existence we call the flesh before we fully awaken to our own innocence.
The man, the one who begged, who has been blind from birth (time-based experience), is surely a figurative telling of who our almost lifelong attachment to the flesh since birth has from the beginning been our blindness to knowing our eternal identity.
he saw a man which was blind from his birth.
 And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind?
 Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
 I must work the works of him that sent me, while it is day: the night cometh, when no man can work.
 As long as I am in the world, I am the light of the world.
 When he had thus spoken, he spat on the ground, and made clay of the spittle, and he anointed the eyes of the blind man with the clay,
 And said unto him, Go, wash in the pool of Siloam, (which is by interpretation, Sent.) He went his way therefore, and washed, and came seeing.
 The neighbours therefore, and they which before had seen him that he was blind, said, Is not this he that sat and begged?
 Some said, This is he: others said, He is like him: but he said, I am he.
 Therefore said they unto him, How were thine eyes opened?
 He answered and said, A man that is called Jesus made clay, and anointed mine eyes, and said unto me, Go to the pool of Siloam, and wash: and I went and washed, and I received sight.
 Then said they unto him, Where is he? He said, I know not