Forshadowing

Foreshadowing be a warning or indication of (a future event).

Examples of foreshadowing
William Shakesphere's Romeo and Juliet uses a lot of foreshadowing as well. "Of a despised life closed in my breast By some vile forfeit of untimely death" Romeo explains in this quote how he thinks he will die an 'untimely death' which he does. Spooky stuff I know.

Quotes
In chapter 3: Huts on the Beach when Jack is talking about hunting Ralph says, "So long as you hunters remember the fire---" And in the following chapter the hunters allow the fire to go out and the boys miss the chance of being rescued.