Why didn't Obi Wan finish off Anakin?

Anakin was lying there with no legs and one arm and Obi Wan just walks away. Wouldn't it have made more sense for Obi Wan to kill him so he wouldn't become the Vader we came to know later?

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Obi-Wan is still there when Anakin bursts into flames. I'm sure at that point, Kenobi figured Anakin was dead.

Maybe he just couldn't bring himself to deliver the death blow.

 

Obi-Wan won the fight. Once he closes down his lightsaber and then picks up Anakin's, there's nothing more to do but express his love to his former apprentice and tell him how wrong he was. He had no intention of killing Anakin.

 

It's pretty un-Jedi like to attack a helpless man.

 

I pretty much agree with GARTH_MAUL. People generally don't survive being consumed by flames, especially in the state Anakin was in. And I thought Obi-Wan had made it very clear that he didn't want to kill Anakin - he tried to convince Yoda to allow him to face the Emperor, and he tried to talk some sense into Anakin - even up to the point right before he delivered that crippling blow, he was trying to stop Anakin from pressing the fight with his "high ground" comment. Obi-Wan did his duty, like he said he would, but he really didn't want to and just couldn't bear to kill Anakin or watch him die, so he left him for dead.

 

I don't think it would have been un-Jedi like to finish off Anakin instead of leaving him to burn and die a slow death, unless Obi Wan was having a sadistic moment and figured that Anakin needed to die a painful death for falling to the darkside. A quick thrust to the heart would have done the trick.

 

I don't think it was as much of Obi-Wan thinking he's dead as it is that it's not the Jedi way. Obi-Wan struck Anakin down and the battle was over. There was no need for any more damage to be done.

For example, in The Phantom Menace when Darth Maul stabbed Qui-Gon, he didn't die immediately, but did Maul chop him up after that point regardless? No.