They rightfully expected the Messiah to be supernaturally sent and yet failed to see Him when He came. The unique claim of Jesus in His controversy with the Jews is “I know him.” Jesus is the Sent One from God and the Revealer of Him to men. (John 1:18)

“The pronoun I in the statement ‘but I know him’ is emphatic, as are the last two pronouns ‘you’ and ‘him’ in v. 28. . .In this manner a strong contrast is made between ‘you’ in the last clause of verse 28 and ‘I’ in the first clause of v. 29.” [UBS]“It is in fact no longer through the Law but through Jesus that God wills to be known, though the Law remains a valid testimony to Jesus and to the revelation given to him.” (Barrett)