Final answer:
Macbeth says the line “Wake Duncan with thy knocking! I would thou couldst!” in Act 2, Scene 2, expressing his guilt and wish to undo the murder of Duncan.
Step-by-step explanation:
The quote “Wake Duncan with thy knocking! I would thou couldst!” is said by Macbeth in Act 2, Scene 2 of Shakespeare’s play, 'Macbeth'. This line is delivered just after Macbeth has murdered Duncan and hears a knocking at the gate. The quote expresses Macbeth’s guilty wish that the knocking could awaken Duncan, thereby undoing the murder he has just committed. The context surrounding this quote involves Macbeth grappling with the guilt and paranoia resulting from his bloody action. Although he has achieved his aim of killing Duncan to take the throne, he cannot escape the psychological consequences of his deed.