Fear, this motivates us to do many things no matter if they are right or wrong. In the play Macbeth it was fear that was the main motivating factor that influenced the outcome of the play. This can be proved by the subsequent murders that followed after Duncan's, why were these committed? Because Macbeth was scared of being caught and having to pay for the wrongs he had done. Also look at Lady Macbeth, the …showed first 75 words of 960 total…

…showed last 75 words of 960 total…after the first of his crimes the rest became easier for him, pretty soon he'd just order it and not think twice. That was not the case when he first murdered Duncan. Although the play his fear of being caught, and the witches prophecies coming true make him do all these evil deeds. Fear and become the main motivating factor in the play. Hopefully you have a better understanding of the play from all this.