Notice the motif of light used in The Lord of the Rings. The Light of Elendil, given to Frodo by Galadriel, was a light for him in the most dire and hopeless of times, like when he fought off the giant (and hungry) spider that tried to kill and eat him. The spider, an instrument of evil, was scared off by the light.
The Hobbit is something of a wonder. On one hand, it's an endearingly unique fantasy romp that will impress fans with it's choice of casting and win over the rest with a mix of charm and stunning visual pieces. On the other, not only is it around 170 minutes long, it's also a bit of a nightmare thinking how Jackson will top this with the next two installments.