15 Unanswered Lost Questions That Totally Have Explanations
7. What Are The Rules Between Ben and Widmore?
In Season 4, Keamy, while working for Widmore, kills Ben's daughter Alex. Ben seems pretty sure that Keamy won't go through with his threats to kill her, so when he does, Ben is shocked and mutters to himself, "he changed the rules." These rules are mentioned again when Ben says he "can't" kill Widmore. So what are these rules, exactly? Are they connected to the rules between Jacob and the Man in Black?
The Explanation: This one is pretty simple. While the feud between Ben and Widmore and their obsession over rules is clearly meant to foreshadow the Jacob/Man in Black dynamic, the rules they're talking about here most likely refer to the Others' internal rules, notably that Others can't kill fellow Others or their relatives. That's first explored in Season 3 when Juliet is punished for killing an Other.
So by having Alex killed, Widmore basically killed a fellow Other, therefore changing the rules. That would be why Ben can't kill Widmore. There's nothing literally preventing him from doing so, but it would be violating the rules.