This is one of the main reasons behind Macbeth's actions and ideals. In act one, scene three Banquo begins to remember the witch's prophecy which then leads Banquo to think suggestively about whether or not Macbeth killed King Duncan to gain the title of King of Scotland. One of the reasons Banquo suspects that Macbeth killed King Duncan is that he was there to witness the witches' prophecies where they basically said that Banquo's sons will become kings and that Macbeth will become king instead of Banquo. Banquo also knew that for Macbeth to become King he would have to go through a lot of people to get to that position of great nobility. So in turn Banquo "presents himself as a sort of moral figure who manages to resist the temptation of the witches" (Ribner page 1). This means that Macbeth, to truly become a king, will in turn have to know that he will have to work hard to achieve his future. In Banquo's case all he has to do is accept the fact that his sons will become kings. Meanwhile the witches give Macbeth another chance in the future by showing him a series of three appearances. The first appearance of a head on the arm was to be worn by Macduff. Subsequently the second apparition meant being wary of a child who did not come from a usual natural birth. Then finally in the third appearance Macbeth learns that he will never have one