What does John 8:24 mean?
Once again, Jesus professes to be the one and only option for salvation. Earlier, when claiming to be "the light of the world" (John 8:12), He made the same suggestion. Then, while debating with the Pharisees, Jesus directly said that those who reject Him "will die in [their] sin" (John 8:21). Since Jesus is sent by God the father (John 8:16), comes from heaven (John 8:23), and does the will of God (John 7:28–29), those who reject Him cannot be saved (John 3:36). To turn your back on Christ is to turn your back on God Himself (John 6:29).This is the context of Jesus' recent comments about going where He cannot be followed. First and foremost, this means returning to heaven after His crucifixion and resurrection (John 20:17). However, it also reflects the fact that these men are running out of time to accept their Savior. At some point, they'll realize they need to seek Christ, but it will be too late (Luke 16:19–31).
Interestingly, Jesus once again uses the "I AM" phrasing here. In the gospel of John, there are seven highlighted moments where Jesus describes Himself using this specific expression. While this is not one of those, the meaning is the same. When God stated His identity in Exodus 3:14, He referred to Himself as "I AM," using a Hebrew phrasing implying necessary existence and absolute truth. When Jesus states in this verse that one must believe "I am he," it's yet another instance where He does, in fact, tell others that He is God.