How does the author use foreshadowing in Faust. First Part?

In "Faust's Study", Faust is initially frightened of the black poodle, though he brings the animal back to his study anyway. His fear of the dog was a foreshadowing of who is masked by the dog's form. As Faust attempts to read and study the scriptures, the dog interrupts and frustrates his study by howling and growling, and then finally transforming into the form of Mephistopheles himself.