What does John 6:28 mean?

The crowd which followed Jesus into Capernaum was seeking a repeat of the prior day's miracle. There, Jesus fed more than five thousand people with a tiny amount of food. Jesus knows, however, that their interest is inherently shallow, and selfish (John 6:26). The people are hung up on material things, such as entertainment and handouts. Christ's discourse in this passage clarifies that His mission is not about bread or recreation. All of these material things pass away eventually, so there is no lasting value in pursuing them. Rather, our focus ought to be on heavenly things, which last forever (John 6:27; Matthew 6:19–20).

In the prior verse, Jesus uses language here which is very specific and would have been familiar to a Jewish audience. The term "Son of Man" comes from a prophecy given by Daniel (Daniel 7:13–14), and points to the long-promised Messiah. Jesus' use of this term, in reference to Himself, is both deliberate and controversial.

After being told to work for this kind of imperishable food, the people ask a question which echoes their preoccupation with ritual, works, and tradition (Romans 10:2–4). Jesus' response, in the next verse, will contradict this sense of works-based salvation. This leads to an indignant reply from the crowd.