As in most expositions, the opening scene of "Macbeth" by Shakespeare establishes a mood. With the three witches's arrival and portentous remark,
Fir is foul, and foul is fair./Hover through the fog and filthy air (I,ii,10-11)
the motifs of evil confusion and the supernatural are introduced. This opening scene also introduces the theme of fate as a force in the action of the play. And, since the Elizabethans were very interested in the elements of the supernatural, this first scene captures the attention of the sixteenth century audience, aristocracy and groundlings alike.