Bilbo didn't steal the Arkenstone
Ivriniel, Bilbo didn't steal the Arkenstone; it was part of the agreed fourteenth share of the profits he was promised in his contract with the dwarves. Thorin also changed the contract to say that he could pick and choose his own fourteenth share; so Bilbo was within his rights to take the Arkenstone; and as it was his personal property, he was entitled to give it away if he wanted.
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