What does John 18:9 mean?
While praying before coming to the garden (John 17:1), Jesus mentioned that He had not lost any of those given to Him by God the Father (John 17:12). To maintain that protection, He has made it clear to His enemies that He is to suffer what needs to happen, not the disciples (Matthew 20:18; John 12:32–33; 13:26–27). Judas and his group of armed men (John 18:1–5) were thrown to the ground by Jesus' power (John 18:6–7), followed by a demand that they leave the others alone (John 18:8).Christ's actions here create a snapshot of the gospel, itself. With complete awareness and knowledge, God Himself stands between His followers and harm, taking on Himself the consequences of hatred and evil (John 3:16; Philippians 2:8).
Presumably, Jesus' desire is clear to the arresting soldiers: to allow the disciples to leave. Peter, however, will once again act stubbornly, trying to make good on his earlier bragging (John 13:37). Other Gospels include more details (Luke 22:49–51), but John simply notes Peter's fumbling attempt at holy war, and Jesus' immediate rebuke (John 18:10–11).