Oh I doubt it. He couldn't even kill the last man who tried murdering him, his father. By next weeks previews Ben is going to undergo "judgment" by the island. So John might come with him but if Ben dies I have a feeling it will be the "island" who kills him. What comes to mind is the smoke monster. Remember how Mr. Eko died? Maybe something like that I'm guessing. But I suppose we'll just have to wait until next week!

I'm not sure but don't think he will. Locke did have a hard time killing his father, ultmately leaving it up to Sawyer but remember he did plant that knife in the back of one of the "rescuers" when they were trying to get off the island. So he has no trouble killing as long as it's for the good of the island.

My question is this: can Ben killed on the island. Remember he was shot by sayid but the island saved him and now he has become one of them, aka "the others". Locke went through the same baptism of fire that Ben did. First, getting shot and left for dead by Ben and then strangled by Ben and then coming back to life once he was back on the island. It's seems to me these guys that are "chosen" can't seem to die on the island.

I don't think it's the black smoke monster. Even the others were afraid of that thing and stayed away. I think that thing is just an inhabitant of the island. Maybe Jacks dad will play a role in this "judgment" we are hearing about. He has been calling the shots so far with Locke so we'll see.

Also, there is no guarantee that Ben will die at all.

Locke couldn't even kill his father, who betrayed him at every turn and he will certainly not kill Ben.

I think Ben will tell Locke he HAD to kill him, and that he knew Locke would come alive once he returned to the island. There's a theory as to why Ben killed Locke that makes sense to me (from source link).

"Because where Locke couldn't find a way out of keeping his word to Jin, Ben did. Ben needed to find a way he could bring Sun back -- without Locke breaking his promise -- and that's precisely what he did."