What's the journey thing in Eragon?

Eragon sets out on a journey that starts with one purpose but evolves into something quite larger. He and Brom begin in pursuit of the Ra'zac, but eventually, as Brom had warned, they were pursued by the Empire itself. Eragon, in becoming a Dragon Rider, becomes the hope of his people against the Empire, which has become evil. King Galbatorix has aligned himself with the Urgals and the Shade and Ra'zac, who terrorize and kill at will. Upon leaving Carvahall, Eragon has a feeling that he will not be seeing his home for a long time and his future, as foretold by Angela, shows this feeling to be a true one.

Saphira later tells Eragon: "It is your wyrd that shapes you, said Saphira. Every age needs an icon - perhaps that lot has fallen to you. Farm boys are not named for the first Rider without cause. Your namesake was the beginning, and now you are the continuation. Or the end. (Page 430)