I am in blood
Stepp’d in so far that, should I wade no more,
Returning were as tedious as go o’er.
– William Shakespeare
Macbeth, Act 3, Scene 4. Macbeth realizes that he has gone so far on the path of evil, that there is now no returning from it. He has been involved in so much murder that it is just as easy to carry on killing as to turn back. He has now become a tyrant. He compares his path to power to a river of blood that he wading through. This metaphor symbolizes Macbeth’s guilt.