I see thee still, And on thy blade and dudgeon gout of blood, which was not so before. There's no such thing. It is the bloody buisness which infoms thus to my eyes. (2: 1. 35-39)
What hands are here! Ha! They pluck out mine eyes. Will all great Neptune’s ocean wash this blood Clean from my hand? No, this my hand will rather The multitudinous seas incarnadine, Making the green one red. (2: 2. 60-64)
I am in blood/Stepp'd in so far that, should I wade no more,/Returning were as tedious as go o'er. (3: 4. 136-139)
In Macbeth, imagery is frequently used. In Act 2, Macbeth uses the appearance versus reality theme in a such a way as to peek my curiousity. He states prior to the murder that he sees the dagger that he shall use to commit the dreadful crime, but is clearly hallucinating as in reality there was no actual dagger in front of him.
Again, blood was used by Macbeth in Act 2, Scene 2, after he commits the murder on King Duncan. He proclaims that not even the blue ocean can wash his bloody hands clean from this deed. This choice of blood imagery strongly represents how he truly feels.
In this part of the book, Macbeth knows he has gone to far and that there is no point of turning back. He makes it clear that he has stepped in the blood so deep that he might as well continue creating more blood.