Rescue 1 (Source)

What does /rescue do, and how do you use it?

/rescue is used by targeting a friendly that is under attack. The effect is that all opponents of the target will immediately aggro the Ranger. If no further action is done, opponents will tend to revert back to attacking the closest target, so it is a good idea for the rescued player to retreat behind the Ranger. It is generally a good idea to begin attacking the opponents in order to retain aggro.