What does John 18:37 mean?
The Roman Empire was relatively tolerant of those they conquered. So long as taxes were paid, trade was uninterrupted, and armies could pass through, the general approach was to let local customs and traditions continue. Jesus' enemies are accusing Him of one of the few things Rome would instantly react to: sedition (John 19:12–15). Their claim is that Jesus has made Himself into the "King of the Jews," supposedly meaning He plans to oppose Roman rule (Luke 23:2).Pilate already knows something about Jesus, thanks to His extremely public reception a few days earlier (Matthew 21:1–11; John 12:12–19). He's dismissive of Jewish culture, in general (John 18:29–31, 35). And it's clear, even now, that all this is a personal vendetta against Jesus (Matthew 27:18; Mark 15:10). Unless there is clear evidence, he's not going to do the scribes' and Pharisees' dirty work for them. Jesus did refer to a "kingdom," however (John 18:36), so Pilate asks a clarifying question. "King" is a dangerous term, but if Jesus does not mean to take political power, Pilate is not going to be concerned.
The response Jesus gives here dovetails with the remark made in the prior verse (John 18:36). The purpose of His first coming to earth is not to establish a government, or a political group, or an army. It's to pass along a message from God the Father (John 8:28), and call people to faith and repentance (Luke 5:32). That includes trusting in Christ, Himself (John 6:28–29), who claimed to be "the Truth" in an earlier passage (John 14:6). In the future, Jesus will establish an earthly kingdom, and He will do so through conquest (Revelation 19:11–15). That will happen entirely by His own work, not through fighting from His followers. But in the most material, immediate sense, Jesus' message is no threat, whatsoever, to Pilate's authority in this part of the world.
Unfortunately, Pilate's dismissive attitude will continue as He responds to the concept of "truth" by literally walking away from the One who is the Way, the Truth, and the Life.