“ As I am his Kinsman and his subject,
Strong both against the deed: then, as his host,
Who should against his murderer shut the door,
Not bear the knife myself. Besides, this Duncan
Hath borne his faculties so meek, Hath been
So clear in his great office, that his virtues
Will plead like Angels, Trumpet toned, against
The deep damnation of his taking off.”
I vii 13-20
This quote is expressing the reasons why Macbeth believes they should not kill Duncan. He is guilty because of the fact that Macbeth is Duncan's host and should invite him in to protect him not to kill him, that the king is a virtuous ruler and that will make his murder more difficult and guilt riddled.
"Deep Damnation" shows an analogy for murder in this context as it is speaking of what is the happen to Duncan in the afterlife, this quotation also uses dark imagery to portray how morbid these thoughts are. Examples of this are "bear the knife" "deep damnation" and "plead like angels" .