Right away, Banquo is more suspicious of the Weird Sisters and their prophecies than Macbeth is. Almost the first thing he wonders about them is if the witches were merely a hallucination. He asks,
Were such things here as we do speak about?
Or have we eaten on the insane root
That takes the reason prisoner? (1.3.86-88)
He does not assume that they were telling the truth, and he finds their provenance suspect. He is, obviously, astonished when the Thane of Ross reveals that Duncan has named Macbeth the Thane of Cawdor, asking, "What, can the devil speak true?" (1.3.113). Once Macbeth learns that the witches' first apparent prophecy has come to fruition, he seems to believe the rest of it immediately. Banquo, on the other hand, still has concerns. He says,
But 'tis strange.
And 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[.] (1.3.134-139)
He suggests that beings with evil intent might purposely tell them small...
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