Hier sind die Originaldialoge:
Ep.V:
Yoda: "Run! Yes. A Jedi's strength flows from the Force. But beware of the dark side. Anger ... fear ... aggression. The dark side of the Force they are. Easily they flow, quick to join you in a fight. If once you start down the dark path, forever will it dominate your destiny, consume you it will, as it did Obi-Wan's apprentice."
Luke: "Vader. Is the dark side stronger?"
Yoda: "No ... no ... no. Quicker, easier, more seductive."
Luke: "But how am I to know the good side from the bad?"
Yoda: "You will know. When you are calm, at peace. Passive. A Jedi uses the Force for knowledge and defense, never for arrack."
Luke: "But tell me why I can't..."
Yoda: "No, no, there is no why. Nothing more will I teach you today Clear your mind of questions. Mmm. Mmmmmmm."
(Laurent Bouzereau: Star Wars - The Annotated Screenplays, Seite 180)
Ep. VI:
Luke: "Master Yoda ... is Darth Vader my father?"
Yoda: "Mmm ... rest I need. Yes ... rest."
Luke: "Yoda, I must know."
Yoda: "Your father he is. Told you, did he?"
Luke: "Yes."
Yoda: "Unexpected this is, and unfortunate..."
Luke: "Unfortunate that I know the truth?"
Yoda: "No. Unfortunate that you rushed to face him ... that incomplete was your training. That not ready for the burden where you."
Luke: "I'm sorry."
Yoda: "Remember, a Jedi's strength flows from the Force. But beware. Anger, fear, aggression. The dark side are they. Once you start down the dark path, forever will it dominate your destiny. Luke ... Luke ... Do not ... Do not underestimate the powers of the Emperor or suffer your father's you will. Luke, whon gone am I ... the last of the Jedi will you be. Luke, the Force runs strong in your family. Pass on what you have learned, Luke ... The is ... another ... Sky ... walker.
(ebenda, Seite 267)
Wie man sieht, ist die Passage in RotJ im großen und ganzen ein Zitat der betreffenden Passage aus TESB.