In William Shakespeare’s play Macbeth, the responsibility for evil rests mainly with Macbeth himself. The witches offer him tempting prophecies and promises, but it is ultimately Macbeth who chooses, of his own free will, to commit evil acts. His wife encourages him, to be sure, but he is capable of resisting her encouragement if he so chooses. Instead, he chooses to do evil, and he finally suffers and dies because of that choice.
One scene in which Macbeth’s responsibility for the evil deeds he commits is very clear is Act 1, scene 7. Macbeth has been considering killing Duncan, but then he tells his wife that he has changed his mind:
Macbeth. We will proceed no further in this business:
He hath honour'd me of late; and I have bought
Golden opinions from all sorts of people,
Which would be worn now in their newest gloss,
Not cast aside so soon.
Although his reasoning here is somewhat selfish (he doesn’t reject the killing because it is morally wrong but because it may damage his reputation), he nevertheless demonstrates here that he does actually have the power to change his mind. However, his wife immediately berates him and calls him cowardly and irresolute. She attacks him incessantly until his resolution begins to crumble. The fact that it takes her so many lines to begin to wear him down shows that he knows that murdering Duncan is wrong, and the longer she talks, the more Macbeth becomes responsible for whatever decision he ultimately makes. If he had changed his mind immediately, we might assume that he acted from uncontrollable, impulsive passion. Instead, he acts after much hesitation, deliberation, and forethought. His only concerns are prudential ones, such as what will happen if they fail.
Finally, at the end of the scene, Macbeth speaks the fateful words:
Macbeth. I am settled, and bend up
Each corporal agent to this terrible feat.
Away, and mock the time with fairest show:
False face must hide what the false heart doth know.
“I am settled” – not “you have talked me into it.” It is Macbeth who makes the decision; it is Macbeth who is responsible for the ensuing evil; and it Macbeth who will suffer the bloody consequences of his choice. He will literally lose his head by the end of the play – a head he has just abused by failing to reason properly.