14+ Macbeth Ambition Quotes Bbc Bitesize. In shakespeare's time people believed in witches. Fair is foul, and foul is fair: Quotes related to ambition within macbeth. Shakespeare had many reasons to write this play, and one . Macbeth speaks these lines as he realizes that the witches' prophecy (that he will be thane of cawdor) has . O search for the topic on the bbc bitesize website. If you would like more on the subject, use bbc bitesize; 5 revision cards about key themes ('big ideas' that shakespeare was writing about). Theme (notes from bbc bitesize and shmoop). Hover through the fog and filthy air.