Unprincipled Ambition in Shakespeare's Macbeth

The Bard of Avon saturates the pages of the tragedy Macbeth with ugly feelings of ambition - unprincipled ambition which is ready to kill for itself. Let's thoroughly search out the major instances of ambitious behavior by the husband-wife team.

 
Samuel Johnson in The Plays of Shakespeare explains the place of ambition in this tragedy:

  The danger of ambition is well described; and I know not whether it may not be said in defence of some parts which now seem improbable, that, in Shakespeare's time, it was necessary to warn credulity against vain and illusive predictions.

The passions are directed to their true end. Lady Macbeth is merely detested; and though the courage of Macbeth preserves some esteem, yet every reader rejoices at his fall. (133)

 

  Blanche Coles states in Shakespeare's Four Giants that the protagonist's ambition was not the usual narrow, personal ambition:

  He has admitted to a vaulting ambition. We have no other evidence of personal ambition except, possibly, his own word in this speech. Onrushing events crowd the thought out of his mind and out of our view. We do have ample evidence of his ambition for his family, ambition for a son who might succeed him. [. . .] We think normally of ambition as a personal thing, but it is not always so. Macbeth's stupendous imagination, as revealed later in the play, gives him a breadth of vision altogether out of keeping with a narrow, personal ambition. (50-51)

 
In "Memoranda: Remarks on the Character of Lady Macbeth," Sarah Siddons mentions the ambition of Lady Macbeth and its effect:

[Re "I have given suck" (1.7.54ff.)] Even here, horrific as she is, she shews herself made by ambition, but not by nature, a perfectly savage creature. The very use of such a tender allusion in the midst of her dreadful language, persuades one unequivocally that she has really felt the maternal yearnings of a mother towards her babe, and that she considered this action the most enormous...