It has been a while but I feel like Yoda and Obi-Wan were really priming him to go fight Darth Vader, talking about he won't be a Jedi until he confronts him. It seemed like they were pointing him at the target in hopes that he'd kill him, and Luke was like "naw."

But I always come back to "I have no idea what the light side of the Force is", so that complicates matters.