That’s not a spoiler. You are Essun, after all. You know this already. Don’t you?
-- Narrator (Chapter 1)

Importance: In Hoa's introduction to Chapter 1, he makes it clear to the reader and Essun that Essun will find her daughter. Hoa claims this is not a spoiler because it should be obvious that Essun would find her daughter again, based on nothing else but who Essun is in the story.

The words, in his lisping toddler-language, are cute. The knowledge that he possesses, because the rock is indeed in Jija’s pocket and there’s no way Uche could have known it was there, dooms him.
-- Narrator (Chapter 1)

Importance: Uche's ability to sess the diamond, Uche's father’s clothing, and Uche's innocent question to his father tip Jija off that his son really is an orogene. For this reason, Jija beats his son to death.

There’s a big hole in the ground up north,’ Nassun...
-- Nassun (Chapter 5)