Why won't Macbeth take the daggers back to the scene of the crime?

Macbeth, the man who is held up as a hero in the opening scenes of the play, is too afraid and too traumatised to go back into the room that he has just left. The room in which he has left the murdered body of Duncan, the king that he has killed. It is Lady Macbeth who takes control as Macbeth is traumatised. He begins to experience the psychological and emotional effects of what he has done - this is why he says 'Macbeth has murdered sleep' and worries that he cannot say 'Amen.' He now has 'hangman's hands' and is beginning to unravel in his mind. His wife now (for a time in the play) represents strength and courage.

Macbeth did not want to take the daggers back to the scene of the crime because he felt guilty about what he had just done - he cannot bear to go back and see it again.