Banquo is another general in King Duncan's army and Macbeth's best friend. While both men have ambitious thoughts, Banquo is more cautious and does not resort to murder to get what he wants.
Banquo is aware that the Witches' predictions may be tricking Macbeth into evil actions and is the first to suspect Macbeth of murder. He dies while protecting his son, Fleance, and comes back as a ghost to haunt Macbeth.
Banquo's thoughts and feelings:
Banquo talks about there being husbandry in heaven, no stars, no light, echoing Macbeth's words about hiding desires from the night
Banquo fixates on heaven to expose the evil Macbeth is about to do
Banquo uses the metaphor of candles being out in heaven, foreshadowing death and linking it with himself
Banquo expresses worry and fear for his son, symbolically giving him a sword for defense