How does the author use foreshadowing in Paradiso?

In line 14, the speaker emphasizes his belief that the reality he seeks is unattainable because he "could never have / imagined" it is possible to find it. Yet "those who came before him", perhaps those who were living proof that one can have more than one path to happiness, have left such an impression on him that he now too believes he can achieve it. This foreshadows the speakers attainment of happiness.