What does John 7:28 mean?
It's hard to tell if Jesus is being serious or sarcastic in His statement that the people "know Him." On one hand, they are aware of His family and His hometown of Nazareth. On the other hand, that familiarity has led many to dismiss Him as the Messiah. In addition, most of these people do not accept Jesus' ministry, or His teachings, as they should. This remark is in response to a suggestion made by some in the crowd: that Jesus cannot be the Promised One since they know where He is from. Messiah, according to their assumptions, should be more anonymous.Jesus' second statement in this verse is much easier to classify. This is a direct criticism of Israel's spiritual state, and an extremely personal reproach. Israel's ultimate point of pride was its identity as God's chosen people. No other nation could make that claim—and here, Jesus tells God's chosen people that they do not know God! Their rejection of God (John 5:39–40) has resulted in a rejection of the One sent by God (John 6:29). Stubbornness and pride have made them resistant to the truth (John 7:17).
As expected, this accusation does not go over well with the people or the religious authorities. Neither does Jesus' claim, from the next verse, that He possesses both divinity and godly approval.