Valentine, Ender's sister, has written a history of the Bugger Wars, and she intends to finish it with a volume about Ender and his work in ending the war. Ender feels that his life after the war is not important, but she thinks otherwise:
"How many more volumes until you're through?"
"Just one. The story of Ender Wiggin."
"Take it up to the day we won the final battle. Stop it there. Nothing that I've done since then is worth writing down."
"Maybe," said Valentine. "And maybe not."
(Card, Ender's Game, Google Books)
Her statements foreshadow Ender's importance later, as he becomes the custodian of the final Bugger Queen egg, which could repopulate their species in peace this time. Also, his own writings as The Speaker of the Dead become the basis of a religion that spreads across the galaxy. His later life become legendary, and Valentine already suspects this; her books reflect his importance both to galactic history and to their own lives.
This statement foreshadows the things in enders life that are worth meaning. Such as in enders shadow