Answer :
During Shakespearean times, monarchs were seen as being God’s deputies on earth, having a ‘divine right’ to rule; the monarch had absolute power, and an attack on him or her, even a verbal one was considered to be a treason. Therefore, the audiences were shocked by Macbeth's plot.
In Act II scene I, as Macbeth is about to kill Duncan, his monologue shows how guilty he feels to commit such crime because he knows it goes against all beliefs