Should I kill the king? I shouldn't be thinking these horrible imaginings...
WHAT, can the devil speak true?
Act 1 Scene 3
Let's talk about the prophecies later...Till then, enough.
Macbeth and Banquo stumble upon the three dirty, ugly witches. The witches then recite a prophecy stating that Macbeth will become Thane of Cawdor, then become king. Along with that, they tell Banquo that his sons will become kings.
Ross and Angus enter to deliver a message sent by the king, which appoints Macbeth as the new Thane of Cawdor. This brings Macbeth to begin having morbid thoughts about how he will soon become king. Along with that, Banquo begins to start noticing the trend that is upon them.
Now that the prophecies are beginning to come into fruition, Macbeth essentially postpones the possible discussion he and Banquo can carry on until later.