John Gill

And Jesus said unto him,.... Giving him the tokens by which he might know him: thou hast both seen him; not that he had seen him before now, with his bodily eyes; for he was blind when Christ anointed him, and sent him to Siloam to wash; nor when he came back, since Jesus was gone, and he knew not where he was; but he had seen him, that is, he had perceived and felt the power of him in restoring him to sight; and now he had seen him bodily, and did at this present time: but as this was not sufficient to distinguish him from other persons in company, he adds, and it is he that talketh with thee; in like manner he made himself known to the woman of Samaria, Joh 4:26.