What does John 18:21 mean?
Jerusalem's religious leaders have already made up their mind to kill Jesus (John 11:53). They are so committed to this conclusion that they arranged to have Jesus arrested in secret (Mark 14:1–2). They've convinced false witnesses to lie about Him (Mark 14:55–59). While going through the motions of a trial, they even asked Jesus to explain Himself (John 18:19). Jesus has already responded that His teaching has always been public—none of these Jewish leaders are confused about what He has taught (John 18:20).The remark Christ makes here is an appeal to fairness. While He has chosen to submit to arrest (John 18:7), abuse (John 18:22), and execution (John 19:15–16). However, He will continue to make it clear that every part of their condemnation is false. Jesus is challenging the religious leaders to present evidence against Him. "Prove it," in short, is His reply in this verse.