Judas leads a group of soldiers and guards to the garden to arrest Jesus (18:2-9). Judas’s role as betrayer is to lead the temple guard to the place where Jesus is camping. It is likely that there are a number of campsites on the Mount of Olives, the Passover crowds probably made finding the exact spot where Jesus was nearly impossible. In addition, it is possible that another person could substitute themselves for Jesus, Judas provides a positive identification of his master.
The solders include Temple guards (who make the actual arrest) and Roman soldiers. Two observations are important about these two groups of soldiers. First, it is historically plausible that the Romans would assign a few soldiers to accompany the Temple guards to arrest Jesus. Passover was a celebration of the Exodus, the time when Israel’s God redeemed his people from their slavery. That imagery was a vivid reminder that the Romans were now the power which “enslaved” God’s people.
Jesus was claiming to be the anointed one of God, he selected twelve disciples who form a new Israel, he rode a donkey into Jerusalem just as Solomon did when he was crowed king, the son of David. The Romans therefore were present to “keep the peace,” or at the very least they were there to keep Jesus from initiating a nationalistic riot.
Second, the two groups represent both Jews and Gentiles. Both come to arrest Jesus and both will have a hand in his execution.
When Jesus speaks, the crowd “drew back and fell to the ground” (18:4-7). Jesus asks the crowd who they are seeking, recalling the first words of Jesus in the book, spoken to two disciples who began to follow him: “What do you want?” When a group representing the whole world arrives, Jesus demands to know their intentions.
Jesus’ response is “I am,” and the guards and soldiers “fell to the ground.” The phrase is rare, the adverb χαμαί appears in Job 1:20, Job fell to the ground in worship; Dan 2:46 (Old Greek), Nebuchadnezzar fell to the ground to honor Daniel (cf. Ant. 20.89). It is hard to know what the solders expected when they went out to the garden, but it was not hearing the voice of God, so powerful that they are driven back in worship!
Jesus specifically asks for the disciples to be left alone, John tells us this fulfills Jesus’ own prayer that not one of his followers should be lost. Peter, however, attacks the servant of the High Priest, cutting off his ear with a short dagger (μάχαιρα). The servant is named in John’s Gospel, although he is unknown to us. (BDAG points out that the name appears in inscriptions, although almost exclusively for Gentiles, Nabatean Arabs (implying that the servant represents the Herodians).
Peter’s actions are sometimes dismissed as laughable, but the represent the actions of the most zealous of Jesus’ followers. Jesus wanted to protect them by giving himself up to the arresting guards, but Peter seizes the moment and “starts the revolution.” Even if this is a colossal failure, it is better than the response of the rest of the disciples!