Act one

Macbeth acts on the witches' prophecies and uses them as an excuse to pursue his own ambitions, whereas, Banquo refuses to act. In fact, Banquo goes do far as to note to Macbeth, "oftentimes, to win us to our harm, / The instruments of darkness tell us truths, / Win us with honest trifles to betray [us]." He sees the evil in the prophecy and alludes to its betrayal.