Foreshadowing

A sign, saying, or image that anticipates, sometimes only for a rereader, something that will happen later in the work.

In Don Quixote

if you wish, gentlemen, that I tell you in few words the immensity of my misfortunes, you must promise me that you will interrupt the thread of my sad story with no question or anything else; for at the point where you do so, there it will end, what I am telling.

The condition that the thread will be lost "at the point where you do so" foreshadows the interruption by the gentleman, which comes shortly after, and the silence asked of the listener is what the listener cannot manage to keep.

Part One: The Galley Slaves and the Sierra, Cardenio, the Ragged One of the Bad Figure, before telling his story

it will not be very difficult to make him believe that a peasant woman, the first I find around here, is the lady Dulcinea.

Part Two: The Printed Book, Sancho, alone, at the gates of El Toboso