Ben Kenobi: There's nothing you could have done, Luke... had you been there. You'd have been killed, too... and the droids would now be in the hands of the Empire.
Luke Skywalker: I want to come with you to Alderaan. There's nothing for me here now. I want to learn the ways of the Force... and become a Jedi like my father.
Luke Skywalker: How did my father die?
Ben Kenobi: A young Jedi named Darth Vader... who was a pupil of mine until he turned to evil... helped the Empire hunt down and destroy the Jedi knights. He betrayed and murdered your father. Now the Jedi are all but extinct. Vader was seduced by the dark side of the Force.
Luke Skywalker: So it is time for the Jedi Order to end.
Master Yoda: Time it is. Hmm. For you to look past a pile of old books, hmm?
Luke Skywalker: The sacred Jedi texts.
Master Yoda: Oh. Read them, have you?
Luke Skywalker: Well, I...
Master Yoda: Page-turners they were not. Yes, yes, yes. Wisdom they held, but that library contained nothing that the girl Rey does not already possess.
Luke Skywalker (about Ben): I saw darkness. I'd sensed it building in him. I'd seen it in moments during his training. But then I looked inside, and it was beyond what I ever imagined. Snoke had already turned his heart. He would bring destruction, and pain, and death, and the end of everything I love because of what he will become. And for the briefest moment of pure instinct, I thought I could stop it. It passed like a fleeting shadow. And I was left with shame, and with consequence. And the last thing I saw were the eyes of a frightened boy whose master had failed him.
Luke Skywalker: Now that they're extinct, the Jedi are romanticized, deified. But if you strip away the myth and look at their deeds, the legacy of the Jedi is failure. Hypocrisy, hubris. That's not true. At the height of their powers, they allowed Darth Sidious to rise create the Empire, and wipe them out. It was a Jedi Master who was responsible for the training and creation of Darth Vader.