How we cite our quotes: All quotations are from Star Wars: The Empire Strikes Back.
Quote #1
LUKE: I'm looking for a great warrior.
YODA: Ah, a great warrior. War does not make one great.
This is Yoda's first lesson for Luke: Being a Jedi isn't all about swashbuckling and adventure. As a relatively young dude, Luke still craves excitement and danger, but he's going to need to get that in check to become a legit Jedi.
Quote #2
LUKE: I don't know what I'm doing here. We're wasting our time.
YODA: (aside) I cannot teach him. The boy has no patience.
Luke's impulsiveness becomes an immediate obstacle to his training. With its Zen-like focus on passivity and peacefulness, the Jedi Order requires a more down-to-earth, humble perspective for its trainees.
Quote #3
YODA: For eight hundred years have I trained Jedi [...] A Jedi must have the deepest commitment, the most serious mind.
In other words, Yoda is an O.G. In addition, this passage re-emphasizes the monastic nature of the Jedi. Though it might seem like all fun and games and lightsabers right now to Luke, the reality is far simpler—and perhaps more boring.