John 9:36

He answered and said, Who is he, Lord, that I might believe on him?

The question is asked by the man healed of blindness, who does not yet know who healed him and wants to know who the Son of God is so that he might believe on Him. He has already acknowledged divine power at work and stands ready to believe when fuller revelation is given. In answer Jesus identifies Himself to him as the Son of God. His restored sight includes spiritual understanding, recognizing Jesus as the One sent by God. Upon recognizing Him the man believes and worships Him.