I addressed that already. Obi Wan is saying that Luke has to be willing to kill Vader, but he’s not sending him to kill Vader, as that would be pointless. The word they use is confront. I already posted this somewhere else but there’s a quote from one of the Timothy Zahn books where Luke talks about this, he says that he assumed that when they told him to confront Vader that that meant he would have to kill him, but that was wrong and that wasn’t necessarily what they meant. Not that that is Disney canon or G canon, but it shows that before the prequels that was the normal interpretation.
Do you remember which book?
In the conversation they’re having right before this exchange, they’re disagreeing on whether or not Vader has any good left in him. I feel like the post-prequel interpretation makes more sense to me than Obi-Wan just wanting him to be prepared to kill Vader.
Why is sending Luke to kill Vader pointless? What’s the difference in sending him to “confront” Vader if he has to be willing to kill him, anyway?
It’s one of the Hand of Thrawn books so either Specter of the Past or Vision of the Future.
It would be pointless because destroying the Empire is already the job of the Rebel Alliance. The Emperor and Vader are going to get blown up. Luke alludes to this. “Soon I’ll be dead, and you with me.” If their only objective was to have Luke kill them then he would have suited up in his X Wing to blow up the Death Star a second time, or they would have wished him good luck on the Endor mission. He had a higher purpose.
He needs to confront Vader to face his fear and resist the dark side in a final spiritual confrontation. It’s a continuation of the events of Empire Strikes Back. He failed in the cave specifically because he brought his weapons with him and he was full of fear. He failed at fighting Vader both because he was unprepared physically, but also spiritually. Now that he has his training, he’s prepared, so he needs to do it. As Yoda tells him, it’s his final trial to become a Jedi. He has to meet Vader again face-to-face, and gain the victory by resisting temptation. That includes the temptation to join Vader because he’s his father.
We should definitely give Luke credit for seeing the good in his father where Obi Wan had given up, but that’s not the same thing as them sending Luke on a military assassination mission.