Five shall go west to the goddess in chains,One shall be lost in the land without rain,The bane of Olympus shows the trail,Campers and Hunters combined prevail,The Titan's curse must one withstand,And one shall perish by a parent's hand.
-- Oracle (Chapter 6 paragraph Page 89)

Importance: This quote from the Oracle sets the five heroes up for their main quest and just in general tells what the book will be about.

Boys are usually forbidden to have any contact with the Hunters. The last one to see this camp…” She looked at Zoe. “Which one was it?”That boy in Colorado,” Zoe said. “You turned him into a jackalope.”Ah, yes.” Artemis nodded, satisfied. “I enjoy making jackalopes…
-- Zoe/Artemis (Chapter 3 paragraph Page 38)

Importance: This is one of the first introductions that readers get to the hunters. It very clearly shows their general disregard that they have for the male gender, while also emphasizing the fact that Percy...