How does the author use foreshadowing in The Last Battle?

In Chapter Four, the King recalls the stories of past visits by the children and calls upon the friends of Narnia for help. The stories about the past gives the reader some background into the previous books in the series. Tirian starts to feel hope and it begins to feel as if he is in two worlds. This foreshadows the arrival of the friends of Narnia who appear in this dream-like state.