system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Why does Yoda say Luke needs to defeat Darth Vader to become a Jedi?
gpt
He actually says he must *confront* Vader, not defeat him.

Anyway, t's the last trial he needs to undertake. Traditionally, Jedi had to take a number of trials before they became full-fledged Jedi - the trials themselves aren't standardized, but individual to each person - and Luke passed most of what the requirements were to be a Jedi, barring one last trial.

So at the time that Luke is getting ready to go to Endor, he's about to face the last trial before he can truly be called a Jedi.