'But here upon this bank of and shoal time'
He is 'netting' the consequences as he stands on the shoal of time, perhaps in an unspoken sea of eternity. This is a very powerful image.
He then suggests that he would risk being damned to become king:
'We'd jump the life to come'
There is a sort of recklessness and instability in the word 'jump', as if to jump off a cliff. 'Life' is a vague euphemism, for hell, Macbeth uses these a lot to avoid associating himself with the act of murder and its spiritual consequnces. The 'we' in this line could be seen the royal 'we' which would show he is already beginning to think of himself as king.
Macbeth also fears the consequences of killing Duncan in this world:
'We still have judgement met here'
He is only thinking of the effects in a practical sense. This shows his military side, thinkiing like a soldier.
Macbeth knows that those who teach "bloody instructions" often find that this comes back to them to "plague the inventor". 'Bloody instructions' along with 'blow' are both euphemisms for murder. Macbeth is still using euphemisms as a comfort to stop himself from feeling the true guilt that his actions will cause.
Macbeth goes onto personify justice as a person handing back a cup of poison:
'This even handed justice
commends th'ingredience of our poison chalice
to our own lips'
This is just one of many images Macbeth uses to explain what he is feeling. He seems to be a very imaginative and this can help to explain his visions later on in the play.
Here the subjects changes. Macbeth starts to list the reason why he should not murder Duncan.
Macbeth realises the King is here in "double trust." King Duncan is a relative, and also a houseguest. Normally, one does not murder one's own relative, especially not if they are a guest in one's own house. Lets not forget that Duncan is also the King so not only is Macbeth killing his relative and guest he is commiting treason. This epithet underlines both the heinous nature of the crime and Duncans vulnerability
Macbeth continues to add to the list of reasons. He reminds himself that Duncan has been:
'So clear in his great office'
Here he is saying Duncan was a great king so it is even more of a crime.
Macbeths use of language starts to have overtones of christianity. These words are examples of this:
'meek'
'virtues'
'angels'
'cherbium'
Macbeth is implying that Duncan is a good Christian king so it is even more of a crime to kill him. Also the words serve as a reminder that the King is appointed by God so to kill him is more than just murder. It is also a crime against God's natural order.
He goes on to use more imagery, Macbeth personfies Duncans virtues as angels who are pleading for Duncans life:
'That his virtues,
will plead like angels'
He makes it clear that this crime is also against God, as it is him who has chosen Duncan for king.
When Macbeth says:
'The tears will drown with grief'
He is acknowledging that the nation will be convusled by grief. Duncans death will not be the death of just one man it will have far wider implications for the well being of the whole nation.
The alliteration of the 'd' in the phrase 'deep damnation' suggests Macbeths horror and disgust at what he will do. The word 'damnation' also makes very clear that Macbeth knows he will end up in hell for this. The following words 'taking off' are another euphemism for murder, he is still avoiding what he must do.
He then personfies pity as a innocent child who is just watching the destruction that Duncans murder will cause. The child is a symbol of vulnerability and innocence, something that Macbeth will destroy if he kills Duncan.
'Striding the blast' and 'horsed' create a military image as he is a horseman. He is like the horseman riding on murder, spurred on by ambition.
'I have no spur
To prick the sides of my intent.'
Here Macbeth admits to himself he has not excuse for what his doing. He is almost digusted by what he will do. He acknowledges there is no reason beyond personal ambition for what he plans to do. Also he fears failure- that he will fall on the other side of this leap.
The dramatic function of this soliloquy is to establish Macbeths state of mind. He is fearful, we see this when Lady Macbeth welcomes a trusting Duncan to Glamis Castle, Macbeth does not attend. This suggests he could not face Duncan, he is feeling very guilty. It also establishes that Macbeth is fully aware of what he is doing wrong and has no excuse. He has free will, he could and probably should have chosen not to do it but chooses to murder Duncan anyway. Also this solioquy takes place whilst Duncan in all innocence is attending a feast in his honour.
