Quote 1
BANQUO
Look, how our partner's rapt. (1.3.156)
"Rapt" comes from the Latin word "raptus," which means to be "seized" or "kidnapped." (Brain snack: It's the same word that gives us "rape," which clues you into the way that women were viewed as property—rape was a crime against a man's property rather than a crime against a woman.) But back to the play: if Macbeth is "rapt," then he's been "seized" by something outside of his control. Does that mean we let him off the hook?
Quote 2
BANQUO […]
My noble partner
You greet with present grace and great prediction
Of noble having and of royal hope,
That he seems rapt withal. To me you speak not.
If you can look into the seeds of time,
And say which grain will grow and which will not,
Speak, then, to me, who neither beg nor fear
Your favors nor your hate. (1.3.57-64)
Uh-oh. Someone's feeling left out. Banquo wants a prophecy, too—although he seems to be much more chill about it, claiming that he doesn't care one way or another. But if that's true, you'd think he wouldn’t bother trying to look into the future.
Quote 3
BANQUO
Thou hast it now—king, Cawdor, Glamis, all,
As the weird women promised, and I fear
Thou played'st most foully for't. Yet it was said
It should not stand in thy posterity,
But that myself should be the root and father
Of many kings. If there come truth from them
(As upon thee, Macbeth, their speeches shine)
Why, by the verities on thee made good,
May they not be my oracles as well,
And set me up in hope? But hush, no more. (3.1.1-10)
Sure, Banquo didn't murder anyone for self gain, but he may not be as honorable as he seems. He suspects Macbeth of foul play, but does he tell anyone? No. In fact, he tells himself to "hush"—maybe because he's a little too excited about being the "root and father/ Of many kings."