By the pricking of my thumbs, Something wicked this way comes.
Act 4 Scene 1 lines 44-45
Said by the second of three witches in Macbeth in Act 4 Scene 1, this phrase became popular in the modern culture. “Something Wicked This Way Comes” by Ray Bradbury is the most iconic example, but this phrase is referred to in lots of the books, films and TV series, from “Harry Potter” to “South Park”.
The witch foresees the arrival of Macbeth, who has already killed both Duncan and his servant. She already senses him as “wicked”, as a murderer and the witches know that his fate will be miserable. So, even if they want to use him in their own evil plans, the later words of Macbeth, accusing the witches and their prophecy, are not completely true. He tries to take off his part of responsibility for what has been done before, but as we see through this quote - he was already evil when he came to the witches to ask them once again. They predicted that he would be the King of Scotland, but he chose the way to fulfil the prophecy by himself. Duncan was very benevolent to him and came to grant him a new title and position - who knows, maybe, if Macbeth was more patient and loyal, Duncan would simply proclaim him his heir?
The witch is right, confirming what we know already: Macbeth showed his true nature by choosing the path of becoming a King. He indeed is wicked from the very beginning.