In Act III, scene iv, of Shakespeare's Macbeth, Macbeth refers to his guilt or his deeds several times.
When he speaks with the Murderer, he casually notes that there is blood on the man's face, and in light that Macbeth is aware of what the man has been doing, reports that the blood is Banquo's. Macbeth further indicates his involvement by asking for the details of his "friend's" murder, noting that the blood outside of Banquo's body is more desirable than in his body:
’Tis better thee without than he within.
Is he dispatch'd? (15-16)
Macbeth's guilt is demonstrated as he acts as if he is insane when he demands who has placed what we infer to be the body of Banquo in the seat set aside for the King:
Which of you have done this? (60)
Macbeth again makes note of the murder of Banquo (and Duncan) as he notes that terrible murders have occurred that should not be spoken of. He also gives specific details of Banquo's death by reported the number of wounds he suffered, as reported by the Murderer:
...murders have been perform'd
Too terrible for the ear. The time has been,
That, when the brains were out, the man would die,
And there an end; but now they rise again,
With twenty mortal murders on their crowns,
And push us from our stools. (93-98)
Macbeth admits to his deed against Banquo when he directly addresses the ghost of the dead man—though no one else can see him:
Avaunt, and quit my sight! Let the earth hide thee!
Thy bones are marrowless, thy blood is cold;
Thou hast no speculation in those eyes
Which thou dost glare with. (112-115)
Lastly, Macbeth speaks again to what he has done—this time referring back to what occurred after he murdered Duncan. His comment not only alludes to his act, but also to the disruption of order in the Great chain of being. When he killed Duncan, he changed the order that God had ordained when he placed Duncan on the throne. These "unnatural occurrences" will continue until the King on the throne is one chosen by God—and that is not Macbeth.