The dwarves have been swinging wildly on a pendulum between optimism and depression. They should probably be medicated. Meanwhile, Bilbo has been taking the seemingly wide rift between his Took and Baggins sides, and he’s melded them together to seek the middle path. To show them all up and prove his resolute, heroic nature, Bilbo even challenges Smaug to show himself while the dwarves cower over the idea that Smaug is simply lying in wait to eat them all. And then Thorin tries so hard to shut him up through rhetoric. It’s pathetic, really.
Be that as it may, the dwarves reenter their home, and the music of golden harps changes the entire atmosphere of the place. Once kitted out with armor, weapons, and jewels, the dwarves see themselves at the end of their quest, once again leaving Smaug out of the calculation.
Bilbo is given his mithril shirt, and his admiring of himself can be seen to harken back to his flattery of Smaug’s diamond-encrusted underbelly. But Bilbo has learned and tempers himself with thoughts of home. And he reminds the dwarves that the opening to this realm is “Smaug’s front doorstep.”
Bilbo still feels he needs to prove himself to the dwarves, and he still remains outside their company. Here, at the pinnacle of his career as a burglar, he starts questioning the very reason they hired him in the first place. After all, there’s far too much treasure for a large army of burglars to haul off the treasure. He didn’t sign up to be a dragonslayer.
According to Prof. Olsen, Tolkien’s original idea was indeed to make Bilbo the dragonslayer. The original version would have had Bilbo drive Sting deep into the weak spot in Smaug’s underbelly, so far that it disappeared, and the hobbit would have to dive into a golden cup to prevent himself from drowning in the sheer amount of blood. That river of blood would sweep the cup and our hero out of the hall while Smaug destroyed it in his death throes. Not bad for a children’s book, huh?
At any rate, it needs to be reminded that the dwarves didn’t hire Bilbo. Gandalf did. Like everything else, the dwarves didn’t plan for him either. Bilbo’s final theft is against the dwarves themselves when he takes the Arkenstone.
The dwarven love of the Arkenstone is a reverence for beauty far beyond the reach of dwarven craftsmanship that all else they’ve ever done is in the attempt to come close to replicating its effects. It was not created by them. It was discovered at the heart of the mountain. To the dwarves, it is the very symbol of everything they hold dear. And yet, it’s not theirs.
Bilbo claims the Arkenstone seemingly against his will, and then he hides it even though he recognizes the moral obligation to tell them of it. Despite the fact that we know what he’ll do with it later (for those of who are familiar with the tale), at this point we understand that if he keeps it, he truly is a thief. Even so, at every turn, we are reminded that when Bilbo takes something, he’s not taking it from the rightful owner. His strength of character and moral integrity give us hope that he will not succumb to the dragon sickness that will take the dwarves.
This idea that Bilbo only repossesses stolen items lends further credence to the oft-presented idea that the Arkenstone itself does not belong to the dwarves. So the theory goes, it is actually one of the great Silmarils of legend. Alas, there is no confirmation of this anywhere in Tolkien’s writing. Then again, there is also no denial either. We are simply left to ask “what if…?”