Return of the Jedi finds Luke becoming a man. Just like that kid on your basketball team who grew six inches, packed on twenty pounds of muscle, and learned how to dunk in the off-season, Luke is bigger, faster, and stronger—not just physically, but psychologically.
When we first meet Luke, he struts into Jabba's palace solo, clad in head-to-toe black, and immediately Force-chokes two of Jabba's thugs. Then he strolls right up to Jabba himself and demands the release of his friends. When Jabba tells Luke, "There will be no bargain, young Jedi. I shall enjoy watching you die," Luke doesn't even flinch.
You don't need to have seen the previous installments in the Star Wars saga to know that Luke is growing up. These aren't the actions of an impetuous kid; these are the moves of a confident, disciplined young soldier.
No Mask for Me, Thanks
Luke 2.0 knows what he wants: namely, he wants to not turn into his dad. Really, though, you'd be hard pressed to find any young man who wants to turn into his father when he grows up. (Dad jeans and classic rock radio 24/7? Nope.)
Of course, for Luke, the stakes are a lot higher than Dockers and Aerosmith. Luke has witnessed his father's path into the gnarled heart of the Dark Side and can sense the conflict in him. That's why he repeatedly rebuffs the Emperor's taunts to "give in to [his] anger" and join the Empire. When the Emperor tells Luke, "It is unavoidable. It is your destiny. You, like your father, are now mine," Luke's trying not to hear that. He doesn't just want to avoid his father's nasty fate. He wants to full-on rescue Darth Vader and rewrite the ending of his story.
Keeping the Faith
Luke's faith is his greatest weapon in the war between good and evil being waged for his soul. The Force is strong him; it's up to Luke to decide how to use it. He can use it for good, like Obi-Wan and Yoda, and embrace the Jedi path of love, non-violence, and friendship.
On the other hand, he can use it for evil, like Darth Vader and the Emperor, and try to rule the world through arrogance, aggression, and an intergalactic closet full of floor-length black robes. They're slimming, sure, but they're also totally evil.
Emotional Ninja Warrior
In his effort to do what's right, Luke plunges himself into a series of increasingly difficult situations, and in each case, he relies on his faith to carry him through unscathed—or at least minimally scathed.
First, he surrenders himself to Darth Vader. Turning yourself over to a dude who's made no bones about the fact that he wants to bump you off? That takes guts. When Darth Vader asks Luke if his surrender means that he's accepted the truth that he's fated to follow his father's evil footsteps, Luke flips the script. "I have accepted the truth," Luke says, "that you were once Anakin Skywalker, my father." Your move, Vader.
Next, Luke is forced to fight Darth Vader head-to-head. Now, we know what you're thinking: "As a Jedi, isn't he supposed to be all about non-violence? Like Space Gandhi?" Fair point, but here's the thing: Luke doesn't want to fight Darth Vader, even stating directly that he will not, but when Vader charges at him with a lightsaber, Luke finds himself in a kill-or-be-killed situation. When it comes down to it, Luke can't save Darth Vader if Luke's dead.
When Luke chops off Vader's hand, he's reminded of how much they have in common—they're just two regular guys who have robotic right hands—and it only bolsters his faith in his father's capacity for redemption. He has Vader on the ropes, but he can't deliver the knockout blow. To do so would go against everything he believes as a Jedi, and it would mean the Emperor was right.
Even as his father hacks at him with his lightsaber, Luke insists that Darth Vader is a good guy:
LUKE: Your thoughts betray you, Father. I feel the good in you, the conflict.
DARTH VADER: There is no conflict.
LUKE: You couldn't bring yourself to kill me before, and I don't believe you'll destroy me now.
You know what? He's right.
The Student Becomes the Master
When Darth Vader refuses to kill Luke, and instead chucks the Emperor down a reactor shaft to his explosive death, Luke's faith is finally rewarded. "You were right," Darth Vader tells Luke, after asking his son to remove his mask so he can finally see him for real:
DARTH VADER: Now, go, my son. Leave me.
LUKE: No, you're coming with me. I'll not leave you here. I've got to save you.
DARTH VADER: You already have, Luke. You were right. You were right about me. Tell your sister you were right.
A parent admitting that their kid was right? That's huge… in any galaxy.
Wait—there's more. Vader doesn't just verbally validate Luke's faith; he also does it through his actions. He sacrifices himself to save his son. In other words, Darth Vader models his behavior after Luke, who was constantly willing to lay his life on the line for dear old dad. In the end, the student becomes the master, the Empire is defeated, love conquers hate, and faith trumps fear.
Luke, we never doubted you for a second, buddy.