How does the author use foreshadowing in The Sacred Journey; a Memoir of Early Days?

Buechner tells the reader from the start that his family is not religious. He often, however, points out the religious importance of various details, as though he himself knows that later, religion will be very important to him. In spite of all this foreshadowing, he does not usually hint at what the details of the conclusion will be, so it is a surprise when he goes to seminary to study to be a minister.