The main lesson of the Star Wars series (one possible reading) is how badly people screw things up when they think they understand "the will of the Force", or, by analogy, some other all-powerful supernatural entity. For example- Qui-Gon (for those who've never seen the prequel movies, well, I'm not going into a complete explanation here- sorry) thought he knew the will of the Force was for him to train Anakin. Result- the end of the Jedi, the rise of Vader, the fall of the Republic, and (so far! I haven't seen the last movie yet) at least 3 generations of turmoil and misery.
People who think they know the "will" of any mystical entity outside of themselves are just deluding themselves and no good will come of them. Yes, religious adherents, I'm talking about you.
Haven't seen the final one yet, but the scene in The Last Jedi that got to me was when Yoda burned down the tree holding the "sacred" Jedi texts that Luke was holding on to; basically saying, Luke put too much stock in the "legacy" he felt he had to hold up, and that that's why he felt he was a failure. I know a lot of die-hard fans were freaking out at the overall the direction that film took, but I thought it was refreshing.
Trouble is (and I still don't get how this came about), the end of the film shows the same books on the shelf in the Falcon. However they got there, that's what I can't work out. It's a mixed message- she doesn't need the books, and yet she has the books to start a new- New Order. I'm stumped.