Why did Obi-Wan let Vader kill him?

[Obi-Ben]

I'm sure this has been discussed to death, but I'm going to ask anyway. Why did Obi-Wan let Vader kill him in A New Hope? He seemed to be holding his own against Vader just fine. Was he getting worn down and knew he was going to lose so he just put an end to it in such a way that he would be a force ghost? I don't think he would have done it so he could benefit Luke--I figure he would be a much better trainer if he were alive. And of course Obi-Wan could have easily blown up the Death Star himself. Did he think Vader wasn't going to let him leave and by dying allowed the rest of the party to escape?

[ArkaiHalon]

"If you strike me down, I shall become more powerful than you can possibly imagine"

By sacrificing himself, Obi-Wan successfully achieved the following:
1. The rest of the group escaped
2. Provided Luke motivation to continue his Jedi training
3. Destroyed the Deathstar
4. Redeemed Anakin

How did he redeem Anakin? wasn't that Luke?
Obi's sacrifice removed the one remaining "spite" Anakin held on to.
By finally defeating Obi, who was the source of his Hate, Vader had no true ties to bind him to the darkside. He held on, for that's what he knew, but he softened dramatically, as evidinced by his finally turning away and in the end, sacrificing himself to destroy the Emporer. Had Obi remained alive, I don't think he'd have ever been redeemed.

[cardcollector]

"If you strike me down, I shall become more powerful than you can possibly imagine"

And,if you remember, he had learned from Qui-gon when on tatooine how to communicate with luke when he was dead.

[Obi-Ben]

And,if you remember, he had learned from Qui-gon when on tatooine how to communicate with luke when he was dead.

But he wasn't really "more powerful." He was just a force ghost. He couldn't do much other than talk.

[B5813]

Look at Obi's face when he's standing before Vader and he looks out to Luke. He kind of smiles when he sees Luke. In my opinion he knows that it's ultimately Luke's destiny to discover who his father is/was and to bring everything to where it ends up being.

[Rhyen Skytracker]

I think Arkai has it right. By making the one sacrifice, he accomplished several task that did make him and the rest of his group stronger, and that was how they destroyed the Death Star and ultimately turned Darth Vader to the light side again.

[Obi-Ben]

Possibly, but I'm not sure Obi-Wan knew that.

[ArkaiHalon]

Possibly, but I'm not sure Obi-Wan knew that.

The look upon his face, the total calm that settled upon him.

He knew.

[Nightwing]

But he wasn't really "more powerful." He was just a force ghost. He couldn't do much other than talk.

But we don't know that. After all, Obi-Wan said on Dagobah that he "could not interfere," as though it was physically possible for him to, but he would not simply out of principle.

Obi-Wan sacrificed himself because LUKE had to be the one to destroy Vader. Obi-Wan was only needed in a guidance capacity, for which he did not need to be alive.
If Obi-Wan had killed Vader, Luke probably would never have become the Jedi he needed to be, and never would have learned the firsthand lessons he needed in order to start the New Jedi Order.

Besides, Obi-Wan was probably going to die of lung cancer in a few weeks anyway. All that Tatooine sand can't be good for you at that age.

[psab keel]

Ultimately if the hero is to succeed in his task, he must lose his mentor in order to gain the courage to complete his quest himself. At the darkest moment the hero must face death by himself.

Obi-Wan was also surrounded by stormtroopers as well as holding Vader off, so it probably made more sense for him to give Luke a chance escape with his friends. That smile that he makes right before he gets cut down is one of my favorite shots in the film. You just can see it all right there. His motivation for Luke's training and the fact that he was ready to become one with the force. I also imagine that he felt a tremendous amount of guilt for what happened to Anakin, despite the fact that it was Anakin who chose to turn to the dark side. I could almost see it as him letting go of his guilt as much as it was sacrificing himself to help Luke and company.