John 9:36 - Ellicott's Commentary On The Whole Bible

Who is he, Lord, that I might believe on him? — For “Lord” it would be better to read Sir, as in John 4:11; John 4:19; John 5:7, et. al. The man does not express by it more than the reverence to a prophet or teacher. He recognises Him by the voice which he had heard before, and now for the first time sees Him. He is ready to believe on the Messiah whom all expected, and he feels that this prophet, who had opened his eyes, can tell him who the Messiah is. The form of the question, “Who is He?” suggests that he half expected that He, upon whom he looked, was more than a prophet, and was none other than the Messiah Himself. In the absence of any such thought, the question would have taken a vague form, such as “Where is He?” or “When shall He appear?” He asks as one who knows that the object of his faith is at hand.