What does John 12:34 mean?

A crowd of people is speaking with Jesus in Jerusalem, not long before Passover (John 12:20–22). In this conversation, Jesus has mentioned His impending death, and received a response from heaven, in the form of audible words (John 12:23–28). Some in the crowd dismissed this as thunder, while others ascribed it to an angel (John 12:29). Jesus pointed out that these signs were meant for the people—as proof they needed to respond (John 12:30–31). All people are faced with a certain level of evidence for God (Romans 1:18–20), and the crucifixion of Christ represents the ultimate "call" that people must either accept or deny (John 12:32–33).

Old Testament prophecy looked forward to the Messiah. However, that perspective didn't include a clear separation of time between events. Most people in this crowd expect the Messiah will come and immediately establish a permanent rule on earth. The question being asked here implies that Jesus' words are not falling on completely deaf ears. Being "lifted up," to some, might suggest ascending to heaven, while others might understand the veiled reference to crucifixion. Either way, it implies Jesus will not be on earth forever.

Earlier, Jesus used the title "Son of Man" for Himself (John 12:23). This is part of the people's confusion, so they ask Jesus to clarify what He means. There is no doubt that He has claimed that phrase—but the people don't understand how that connects to being "lifted up." In a sense, they're asking if Jesus means "Son of Man" in a different way than He's been using it. His answer will flow from prior comments: that there's a clear choice between belief and disbelief, and a person's time to make that decision is limited (John 12:35–36).