Moments before Ross and Angus enter the scene, the Three Witches give Macbeth and Banquo favorable prophecies. The Three Witches call Macbeth the Thane of Glamis, the Thane of Cawdor, and future king before telling Banquo that he will be lesser than Macbeth but greater and inform him that his descendants will rule Scotland for generations. When Ross and Angus enter the scene, Ross announces that King Duncan has named Macbeth the Thane of Cawdor, which is astonishing news to the two men. Both Macbeth and Banquo are taken back by the news and immediately question the witches' intentions. Macbeth instantly begins thinking about becoming king while Banquo is more discerning and has his doubts about the witches' intentions. Macbeth's ambitious nature is revealed during his aside when he begins to contemplate committing a serious crime in order to attain the throne. Macbeth even goes into a trance as Banquo, Ross, and Angus continue their conversation. Once Macbeth comes out of his daze, the men agree to visit King Duncan as Macbeth and Banquo plan on continuing their conversation in the near future. Both Macbeth and Banquo are intrigued by the witches' prophecies but have different reactions regarding whether or not they can trust them.

After the witches tell Macbeth and Banquo the prophecy (that Macbeth will become Thane of Cawdor and later king, and that Banquo's children will becomes kings), they run into Ross and Angus. The men give news that the King has decided to make Macbeth Thane of Cawdor. This is good news, of course, but it also shows that the prophecy might actually be true.

The two men react differently. Macbeth believes the prophecy and asks Banquo if he wants his children to be kings. Banquo distrusts the witches and comments that the devil often tells half truths. The two men agree to speak on the prophecy later in private. Macbeth is already wondering if he will become king naturally or if he will have to take the throne through dark deeds.The split reaction shows a difference in character between the two men. Macbeth, overcome with ambition, can think only of his chance at power, while Banquo is much more concerned about how the witches might deceive him into committing evil deeds.