Relate this quote "By the pricking of my thumbs, Something wicked this way comes." to the importance of the witches in the play and how the afect the characters

This is actually the origin of the famous phrase. The pricking of one's thumbs an intuitive feeling, a foreboding, often with allusion to the words of the Second Witch in Shakespeare's Macbeth (1606) as Macbeth approaches, The witches sense the evil in Macbeth: an evil that they seek to manipulate.