How does the author use foreshadowing in Monkey?

Wen-ch'iao hears a voice when she is giving birth to her son, Hsuan Tsang. The reader doesn't know whose voice it is at the time, but later in the story it will be revealed that the voice was that of Kuan-yin. The importance of the child is hidden to the reader, but there is foreshadowing showing his destiny. The child, Hsuan Tsang, will be the scripture-seeker that Buddha is looking for and will also be the one that frees the Stone Monkey.