I need to know how the witches' prophecy of Macbeth's coming greatness acts as a temptation for him?

The temptation for power and ruler-ship was too much for Macbeth to overcome.  Had the witches not shown Macbeth the prophecy he would gone down a different path.However, once the prophecy was revealed he could not resist and his sinful nature surfaced.  As soon as he hear that he would rule, he went to his wife and they planned how to bring about this succession more quickly.  He then began to kill off anyone he though might jeopardize this power.  The taste for power is a strong temptation for people and it was Macbeth's weakness.