Going on from there was the bravest thing he ever did. The tremendous things that happened afterwards were nothing compared to it. He fought the real battle in the tunnel alone, before he ever saw the vast danger that lay in wait.
p. 215
“He fought the real battle in the tunnel alone.” It might be more exact to say he fought the real battle in his mind. A hero wins the mental battle before he ever enters the arena, before he ever rescues the weak, before he ever braves the deeps. And Bilbo decided first. He hardly decided when he left Bag-End—there, he was practically thrust out. But once on the road, he didn’t turn back. And once in the tunnel, he didn’t turn back. The tunnel was just an extension of all the other little decisions.
Lingering Over Leaves 