In the tragedy of MacBeth, there are a number of people who are to blame for the way the play turned out in the end. This blame ranges widely from minute involvement to being almost directly responsible by encouraging MacBeth to commit the sins that he did in his greedy and selfish attempt to fulfill a prediction made by the Weird Sisters, who, in this play, are aptly dubbed as "witches". But these witches were not the sole parties at fault. There was also Lady MacBeth, who was in full support of her husband's becoming king, and who helped commit a number of sins to assure his ascension to the throne. Then there was also MacBeth himself. He committed the most murderous atrocities in the play and was willing to sacrifice anything and anyone, including his best friend Banquo and his beloved king and friend Duncan so long as he could attain the total power that he desired. He began with the murder of Duncan, and succeeded in gaining the complete power he wanted as the new king. And this desire for total control is what eventually sent him down his path towards self-destruction. .
It is possible to look at the witches as having the smallest level of blame. They were the ones who told MacBeth about his possible future, saying, "All hail, MacBeth! Hail to thee Thane of Glamis. All hail, MacBeth! Hail to thee, Thane of Cawdor! All hail, MacBeth, that shalt be King hereafter!" (I,iii,50-55) They were the first to put the idea of such a future in MacBeth's head, and originally he chose not to act on it, but instead to wait and see if it would come true. And the witches could have just left it at that, but they didn't. They returned later in the play, during Act IV, and this time presented three apparitions to MacBeth including an Armed Head, a Bloody Child, and a Child Crowned bearing a tree in its hand. These signified that MacBeth should beware MacDuff, that he could not be harmed by any man of woman born, and that he would not be defeated until Birnam Wood comes to Dunsinane, another of MacBeth's castles.