During Jesus' arrest, one of his followers strikes the servant of the high priest and cuts off his right ear. Luke then uniquely records Jesus healing the wound.
The victim's designation matters because a high priest's household could include servants and agents involved in its affairs.
Elite households in the Roman world could include enslaved and free dependents performing domestic, administrative, and representative functions. The Greek word used for the man can denote a slave or servant. John names him Malchus, while Luke emphasizes Jesus' healing response.
The Gospels do not specify the man's precise office or why he personally accompanied the arresting party, so elaborate reconstructions of his role should be avoided.
The social setting sharpens the irony of the scene. Violence is directed at a dependent member of the very household associated with Jesus' prosecution, yet Jesus refuses to let his arrest become an armed struggle.
Luke's healing of the servant makes that refusal active: Jesus repairs the injury caused by one of his own followers even as he is being taken into custody.