They know who Jesus is. They know his parents Mary and Joseph. This is Jesus, and he did not come down from heaven. These words are not just complaints. They are argumentative. Jesus, in effect, tells them to “shut up” (verse 43). The language is “stop grumbling among yourselves.” It has the logic of “stop talking and listen to me.” These words decisively indicate that the Jews have not yet understood anything that Jesus has said. This point in the conversation is a rich juncture — the breakdown of understanding could not be any more distinct.