Answer:
People believed in the power of prophecies.
Step-by-step explanation:
At the beginning of the play, a group of witches tell Macbeth that he is a "charmed" person, and that no person born from a woman can hurt him. This makes him ambitious, and feeling blessed, Macbeth commits all the crimes of the subsequent scenes. However, when he is about to face Macduff, he learns that he is not "born" from woman, as he was born by C-section. Macbeth believes in the power of prophecies, as was common during this time period. Therefore, he becomes extremely scared at hearing this, curses the witches and refuses to fight Macduff.