Revenge of the Sith: Obi-Wan: Send me to kill the Emperor. I will not kill Anakin. Yoda: To fight this Lord Sidious, strong enough, you are not. Obi-Wan: He is like my brother. I cannot do it. Yoda: Twisted by the darkside, young Skywalker has become. The boy you trained... gone he is. Consumed by Darth Vader. Obi-Wan: I do not know where the Emperor has sent him. I don't know where to look. Yoda: Use your feelings Obi-Wan, and find him you will. Return of the Jedi: Luke: There is still good in him. Obi-Wan: He's more machine now, than man. Twisted, and evil. Luke: I can't do it Ben. Obi-Wan: You cannot escape your destiny. You must face Darth Vader again. Luke: I can't kill my own father. Obi-Wan: Then the Emperor has already won. You were our only hope. I have repeatedly said that Yoda was wrong to claim Anakin was already totally consumed. When I noticed how similar Yoda's instruction was to ROTJ Obi-Wan's, I realised that it fits in perfectly with my theory that Yoda was wrong in this Ep3 scene. The similarity in he and Obi-Wan instructions backs up my point really strongly. Obi-Wan also said Anakin was gone, but Luke knew otherwise. Yoda said Anakin was gone, but we know he is still partly there until the second-last Vader scene in the movie. I think Anakin could (possibly) have returned in Episode 3 if Yoda hadn't given Obi-Wan this advice.