YODA: No more training do you require. Already know you that which you need.
This is where we really found out that Vader was Luke's father. Up until now we were just like Luke - we didn't know for sure, and we didn't want to believe it. Vader was evil; he must have been lying. Well, he wasn't, 'cos Yoda says so.
More will come, more will come.
The Phantom Menace -
Attack of the Clones -
Revenge of the Sith -
A New Hope -
The Empire Strikes Back
LUKE: Then I am a Jedi...
YODA: Oh, heh-heh-heh! Not yet. One thing remains - Vader. You must confront Vader! Then, only then, a Jedi will you be. And confront him you will.
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.