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.

– William Shakespeare

Macbeth, Act 1, Scene 3. Banquo shows himself to be much more cautious than Macbeth in reacting to the Witches’ prophecies. He calls attention to the danger of acting on the predictions of the evil “instruments of darkness,” as he metaphorically describes the Witches. They may be telling a little truth in order to gain their confidence, so that they can deceive and betray them into causing harm, he warns. This is foreshadowing of Macbeth’s fatal decision to kill King Duncan. This passage raises the question: do the Witches control people’s fate, or do people have free will to decide their own fate, regardless of what the Witches prophesy.