1. Luke: “How did my father die?”
Ben: “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.”
In Episode IV: A New Hope, Luke asks Ben Kenobi this question in Ben’s home, just after Ben gives Luke his father’s lightsaber. Ben’s careful reply is technically accurate in all that it says, but it omits the crucial detail, which is that Ben’s pupil and the good Jedi, Luke’s father, that the pupil “betrayed and murdered” are one and the same. One of Luke’s greatest desires is to know his father, and Ben fears that if Luke knew the truth, he would either despair or, even worse, seek to become just like him. Instead, Ben hopes to encourage Luke to emulate the good side of his father’s legacy, the side that Anakin betrayed when he turned to the dark side and became Darth Vader. Ben takes a great chance here, risking the loss of Luke’s trust should he discover the full truth. And, indeed, Luke is greatly hurt by the revelation when it comes, calling out to Ben in anguish as he speeds away from Bespin aboard the Millennium Falcon.
Later, back on Dagobah, Ben explains that what he told Luke was indeed true, if only from a “certain point of view.” Luke is frustrated by this response, but Ben maintains that many of the things we believe are true in this sense alone. In part, Ben confesses, he hid the truth out of guilt and shame, since Anakin Skywalker was Obi-Wan Kenobi’s greatest failure. Ben, back when he was Obi-Wan, had been in charge of training Anakin but lost him to the Emperor and the dark side. Ben tells Luke that his greatest fear is of losing Luke the way he lost his father. Luke was always meant to know the full truth, but Ben and Yoda had hoped that Luke’s deepening understanding of the Force would lead him to see the truth on his own. Luke’s anguished resentment of Vader’s revelation only shows how unready he was for the truth. Evidence of how much Luke has grown at this point comes when he instantly understands that Leia is his sister, as soon as Ben hints at it.