What is the role of Banquo in Macbeth? Does he help us understand Macbeth better?

In Shakespeare’s “Macbeth,” Banquo is a foil for Macbeth.  The definition of a foil is a character who provides a contrast to another character in order to show that character’s flaws. Banquo is an excellent example of a foil. Both Macbeth and Banquo are brave soldiers, members of the nobility, and respected by the king. Shakespeare shows key differences between the two, though. When the men meet the witches, Macbeth is immediately interested in them. Banquo, on the other hand, is suspicious of them. Instead of immediately accepting them, he laughs at and dismisses them. When the witches give Macbeth a prophecy, Macbeth is both fearful and intrigued. Banquo, on the other hand, is skeptical. He tells them that if they are able to make predictions, they should make one for him. When they do, he makes light of their cryptic remarks. While Macbeth is inclined to believe them, Banquo is more cautious, warning his friend that witches cannot be trusted. “Oftentimes, to win us to our harm/ the instruments of darkness tell us truths/ Win us with honest trifles to betray ‘s/ in deepest consequence” (Act I, Scene 3).

Banquo is strong; Macbeth, weak. Banquo hears the prediction that his sons could be king, and he resists the temptation to make the prediction come true. Macbeth, on the other hand, begins to think about how he can make his prediction come true. He is undecided almost to the moment of the murder, and he allows his wife to push him into doing what he knows he should not do. Conversely, Banquo, when pressured by Macbeth, refuses to commit to doing what he knows is wrong: "but still keep/ my bosom franchised and allegiance clear” (Act II, Scene 1).

Banquo is honorable. After Duncan’s murder, he suspects Macbeth. He could have, for the sake of his own safety, gone along with Macbeth’s story and remained loyal to him. He chooses the honorable path by claiming that he will have nothing to do with this treasonous act, saying, "and thence against the undivulged pretense I fight/ Of treasonous malice” (Act II, Scene 4). Banquo signs his own death warrant with that sentence, and he most likely understands that as a consequence, but he makes the honorable choice. Banquo’s character exists to point to the many flaws in Macbeth.