What does John 6:36 mean?

Jesus is clarifying the purpose of His ministry. Spectacular miracles and free food are not the point of His mission on earth. Nor are they meant to be the focus of a Christian's life. Instead, we ought to be focused on eternal things. First, this means coming to saving belief in Christ (John 6:27–29). Jesus has contradicted the idea of salvation based on good works, teaching that salvation is found only by those who believe in the One sent from God (John 3:16–18, 36; Acts 4:12).

Earlier, Jesus explained that Nicodemus ought to recognize the means of salvation, since he was an expert in the Law (John 3:9–10). Christ refused to let the Samaritan woman sidestep His message with appeals to controversies (John 4:19–21). Jesus criticized the Pharisees for having access to God's written words yet failing to recognize Him as Messiah (John 5:46–47). Here, Jesus points out that the crowd has seen more than enough—in the form of miracles—to realize the truth He is explaining. Yet the people stubbornly refuse to believe. Instead, they ask for even more miracles, as if that would finally convince them (John 6:30).