The soliloquy which immediately follows the above passage is particularly worthy of comment: 

  “This supernatural soliciting
  Cannot be ill; cannot be good:—­if ill,
  Why hath it given me earnest of success,
  Commencing in a truth?  I am thane of Cawdor: 
  If good, why do I yield to that suggestion,
  Whose horrid image doth unfix my hair,
  And make my seated heart knock at my ribs
  Against the use of nature?  Present fears
  Are less than horrible imaginings. 
  My thought, whose murder yet is but fantastical,
  Shakes so my single state of man, that function
  Is smothered in surmise, and nothing is,
  But what is not.”

The early portion of this passage assuredly indicates that Macbeth regards the communications of the witches merely in the light of an invitation to the carrying out of a design pre-existent in his own mind.  He thinks that the spontaneous fulfilment of the chief prophecy is in no way probable; the consummation of the lesser prophecy being held by him, but as an “earnest of success” to his own efforts in consummating the greater.  From the latter portion of this soliloquy we learn the real extent to which “metaphysical aid” is implicated in bringing about the crime of Duncan’s murder.  It serves to assure Macbeth that that is the “nearest way” to the attainment of his wishes;—­a way to the suggestion of which he now, for the first time, “yields,” because the chances of its failure have been infinitely lessened by the “earnest of success” which he has just received.

After the above soliloquy Macbeth breaks the long pause, implied in Banquo’s words, “Look how our partner’s rapt,” by exclaiming,

  “If chance will have me king, why chance may crown me,
    Without my stir.”

Which is a very logical conclusion; but one at which he would long ago have arrived, had “soliciting” meant “suggestion,” as most people suppose it to have done; or at least, under those circumstances, he would have been satisfied with that conclusion, instead of immediately afterwards changing it, as we see that he has done, when he adds,

        “Come what come may,
  Time and the hour runs through the roughest day!”

With that the third scene closes; the parties engaged in it proceeding forthwith to the palace of Duncan at Fores.

Towards the conclusion of the fourth scene, Duncan names his successor in the realm of Scotland.  After this Macbeth hastily departs, to inform his wife of the king’s proposed visit to their castle, at Inverness.  The last words of Macbeth are the following,

  “The prince of Cumberland!—­That is a step,
  On which I must fall down, or else o’erleap. 
  For in my way it lies.  Stars, hide your fires! 
  Let not light see my black and deep desires;
  The eye wink at the hand; yet let that be,
  Which the eye fears, when it is done, to see.”