What does John 1:50 mean?
Nathanael was so impressed by Jesus' knowledge (John 1:48) that he proclaimed Him the King of Israel (John 1:49). Jesus points out that the signs coming soon are even more impressive. A common modern English expression captures this idea: "You ain't seen nothin', yet!"The gospel of John discusses seven of Jesus' miracles, referring to them as "signs." The purpose of a true miracle is always bringing people a message about God or from God. In the gospel of John, these seven miracles are recorded specifically so that people will realize that Jesus is God. Knowing where Nathanael was, and what he was doing, is impressive. But these future signs will be more potent proofs that Christ was who He claimed to be.
Jesus has already gently corrected Nathanael for using stereotypes (John 1:47). Here, He gives an early reminder that those who believe only when they have a miracle are not seeking honestly. Christ makes this point very clear later, in His parables and conversations (Luke 16:31, Matthew 12:39).