Some games have a concept of balance, between things like the forces of Good and Evil, or Law and Chaos. You can have other balances as well - another classic one is balance between elemental forces: Air, Fire, Earth, Water. (Maybe adding/substituting others like Wood, or Heart, depending on your sources.)
One way to make these matter in your game is to introduce the concept of the cosmic balance, and then of course do something to disrupt it. Make the imbalance have consequences that the PCs can notice, and then they have to figure out what's going on, and how to fix it.
Or they can just ignore it and try to collect treasure while the world goes to pieces.
Commentary by memnarch (who has not seen the movie)
Aha! So the tree is still important; that's good to know. And while this is all plausible information, I think this being a temple for balance is a little more likely to be comic original than movie-sourced, even considering the floor artwork in the last comic. It's difficult sometimes to keep the info and feel I remember from the first six movies and the Expanded Universe parts separate from the comic, but I don't think Disney would try to pull something like that. It sounds too much like something that already existed that they would disregard.
Is that a riding crop Luke is holding? I can't imagine why he'd have something like that. There's basically no riding animals on this planet. It's gotta be a weird training tool of some kind though, right? Maybe the goal is going to be to levitate the bit on the end without moving the rest of the stick? We haven't seen anything that's definitively a Force Power yet in this part of the plot, so I'm hoping it's time we get to see something here.
Rey: So what’s this cave about?
Luke: It’s the first Jedi Temple. Dedicated to the balance between Light and Dark. Before they realised balance is precarious, and it led to terrible things.
Luke: They built it here because of the tree. It’s a midi-chlorian focus.
Luke: It only looks dead because it holds midi-chlorians to itself, rather than shed them in leaves.
Rey: So this temple is a focus for midi-chlorians? Or shields people from the tree or something?
Luke: Nah. I just like to come up here to eat my lunch. I thought it’d be a good spot for your next lesson.
Rey: Any other info dumps you need to tell me?
Luke: I think I’ve covered everything on this sheet.
GM: Good roleplaying. Until now.
Luke: Right, your lesson. Balance on this precarious ledge.