“Let’s have no more argument. I have chosen Mr. Baggins and that ought to be enough for all of you. If I say he is a Burglar, a Burglar he is, or will be when the time comes. There is a lot more in him than you guess, and a deal more than he has any idea of himself. You may (possibly) all live to thank me yet.”
Gandalf speaks these words in Chapter 1 shortly after Bilbo faints from terror at the prospect of going on the quest with the dwarves. After Bilbo’s display of fear, the dwarves are skeptical that Bilbo will make a good addition to the party, and Gandalf gives this speech to ease their doubts. The speech is important both because it exemplifies Gandalf’s habit of insisting that his own authority be taken as definitive proof and also because it foreshadows Bilbo’s transformation into a hero. The trajectory of the novel from this point forward essentially involves Bilbo’s discovery of the “lot more in him” that even he does not yet know.