Macbeth has served King Duncan faithfully. Macbeth has been a soldier--a good soldier. He has fought side by side with Banquo. Macbeth has followed a code of ethics. He has faithfully served King Duncan by fighting for him. Macbeth seems content fighting as a soldier until he meets the witches.
When the witches plant "black and deep desires" in Macbeth, he begins changing. With the witches' prophecies, Macbeth begins to covet the throne. He begins to desire to have what belongs to King Duncan.
There is a conflict within Macbeth from this point in the story. He shares his "black and deep desires" with Lady Macbeth. She runs with the idea of Macbeth becoming king. Lady Macbeth and Macbeth begin plotting the death of King Duncan.
Later, Macbeth has changed his mind and tells Lady Macbeth that they will proceed no further with the idea of murdering King Duncan:
We will proceed no further in this business.
He has recently honored me, and I now have the
Golden opinions from all sorts of people,
Which I want to enjoy for a bit longer, and
Not cast them aside so soon.
Macbeth admits that King Duncan has honored him. He has decided to go against his "black and deep desires.' He has decided that he will bask in the honors that King Duncan has bestowed upon him. Now, Macbeth has decided that he will not proceed with any plans to murder King Duncan.
Here, there is a conflict within Macbeth. He realizes that King
Duncan has recently honored him. King Duncan has bestowed honor upon Macbeth. Now, Macbeth has good thoughts that conflict with his "black and deep desires." He has decided that he will receive King Duncan's honor with gratitude instead of malicious desires. Truly, Macbeth has ideas that are conflicting one with the other. Macbeth has decided to enjoy his honors bestowed upon him. He no longer desires to pursue his evil desires.
While this would have been the end of the story, Lady Macbeth manipulates Macbeth. Lady Macbeth convinces Macbeth to act upon his "black and deep desires."