How we cite our quotes: All quotations are from Star Wars: Return of the Jedi.
Quote #4
YODA: No more training do you require. Already know you, that which you need.
LUKE: Then I am a Jedi.
YODA: Not yet. One thing remains: Vader. You must confront Vader. Then, only then, a Jedi will you be. And confront him you will.
Luke's confrontation with Vader is the climax of the movie's plot. That's why Yoda hypes it, Obi-Wan hypes it, Luke hypes it, and Darth Vader hypes it. Luke facing Vader pits good versus evil; no wonder it's the main event.
Quote #5
OBI-WAN: Your insight serves you well. Bury your feelings deep down, Luke. They do you credit, but they could be made to serve the Emperor.
Obi-Wan's advice is sound: The Dark Side of The Force is fueled by anger, hate, and aggression. Luke needs to keep all of those emotions in check if he wants to keep The Emperor from exploiting them and turning him into Darth Vader, Jr.
Quote #6
THE EMPEROR: Come, boy, see for yourself. From here, you will witness the final destruction of the Alliance and the end of your insignificant rebellion.
[Luke eyes his lightsaber]THE EMPEROR: You want this, don't you? The hate is swelling in you now. Take your Jedi weapon. Use it. I am unarmed. Strike me down with it. Give in to your anger. With each passing moment you make yourself more my servant.
LUKE: No.
THE EMPEROR: It is unavoidable. It is your destiny. You, like your father, are now mine.
The struggle between good and evil doesn't just play out in Luke's physical altercations with Darth Vader and The Emperor. It also rages inside Luke himself. Speaking of an angel on one shoulder, and a devil on the other. Luke has a Yoda and an Emperor—each trying to pull him in opposite directions.