What does the following quote mean in Macbeth?
I am in blood/Stepp'd in so far that, should I wade no more,/Returning were as tedious as go o'er. (Act 3, Scene 4)
Macbeth is saying that he is stuck, and can neither go back nor forward. He is forced to stand his ground, since he has made his decision to kill Duncan.
At this point in the play, Macbeth has made his bed. He has already killed Duncan, so there is no turning back. Yet he struggles a little. He is not sure what to do, and needs some time to think things through.
I will tomorrow,
And betimes I will, to the weird sisters.
More shall they speak; for now I am bent to know,
By the worst means, the worst. For mine own good
All causes shall give way. (Act 3, Scene 4)
Ironically, as Macbeth is trying to figure things out to make sure he’s not in over his head, Hecate is scolding the Weird Sisters for messing with him—and deciding to make things even worse by showing him more visions. He thinks he is going to solve something by visiting the witches again to seek their advice, when they are really going to twist him up further and get him into more of a mess.
Lady Macbeth is disturbed by this kind of talk. She tells Macbeth he just needs some sleep. He is acting strangely, and she feels like she is losing control of him.
Macbeth is realizing that after he has committed murder, there is no going back. He immediately regrets killing Duncan, but there is nothing he can do to change what has already happened.