Macbeth takes seriously the question of whether or not fate (destiny) or human will (choice) determines a man's future. Shakespeare seems, ultimately, to be interested in what it is that causes a seemingly decent man (Macbeth) to commit evil acts. On the one hand, the play is set in motion by the weird sisters' prophesy that Macbeth will be king, which turns out to be true. It also often seems that outside forces (related to the weird sisters, who are in many ways associated with the three fates) control Macbeth's actions. On the other hand, the play goes out of its way to dramatize how Macbeth deliberates before taking action, which suggests that he alone controls the outcome of his own future. Alternatively, some critics suggest that Macbeth's fate may be set in stone but his choices determine the specific circumstances by which he arrives at or fulfills his destiny. In the end, the play leaves the question unanswered.
Macbeth raises the question of whether free will or fate determines man's future but the play leaves the questioned unanswered, which suggests that, sometimes, human actions are completely ambiguous – we often never know why people behave the way they do.
In the play, Macbeth is fated to be king but he decides all on his own that he will murder Duncan in order to obtain the crown. This suggests that man's fate is predetermined but human will ultimately determines how man will reach his destiny.