How does the author use foreshadowing in Year of Wonders?

The first conversation about plagues happens at Bradford Hall when a guest shares news of what he has heard from London. The Bradfords and their guests think it is madness not to run from the plague if you have the means, an idea which Mompellion wholeheartedly refutes. His adamant view on this foreshadows what he will ask of his congregation.