Actually he starts killing before the play starts. He is a soldier and used to chopping people in half "from the nave to the chops".
Lady Macbeth receives the idea that her husband should kill the king after reading a letter from Macbeth describing the witches' prophecy. The prophecy states that Macbeth will become king, leading Lady Macbeth to convince him to take action and seize the throne.
In Shakespeare's play "Macbeth," the idea that people should be killed originates primarily from Lady Macbeth. She is the one who convinces Macbeth to kill King Duncan in order to fulfill the witches' prophecy and secure his place as king.
Banquo's ghost, which shows up at the dinner party the Macbeths are throwing. Only Macbeth can see him.
It was her idea to kill him and she convinced her husband to do the deed. She thought Duncan looked like her father so she basically nagged Macbeth into killing him, but she did have guilt over it.
The witches don't make Macbeth perform any dark acts, such as killing King Duncan; they just put the idea in his head. The witches tell Macbeth he is the Thane of Cawdor (which he doesn't know yet) and also tell him that he will be king. Once Macbeth finds out he is in fact the Thane of Cawdor, he begins to believe the witches' prophecies. Lady Macbeth convinces him that the only way Macbeth can be king is by killing King Duncan, and he does so. The witches' role in making Macbeth a tragic hero is to serve a catalyst for Macbeth's dark thoughts.
In Scene 1 of Macbeth, Macbeth vows to ponder whether the prophesied crown will fall into his hands by chance or through violence. This vow is carried out in Scene 2 when Macbeth starts to contemplate the idea of killing King Duncan in order to take the throne.
Well, i wouldn't call what Macbeth did in response to Lady Macbeth's plans for him dealing. I would call it giving in. She questions his manliness when he expresses a dislike against the idea of killing the king so he can become king. As a result of her questioning, he gives in to her plans, though we can see it is somewhat reluctantly.
Macbeth experiences internal conflict over the idea of killing King Duncan to fulfill the witches' prophecy and become king. He grapples with his ambition and his conscience, struggling with the moral implications of murdering his own king.
After Banquo leaves, Macbeth is consumed with thoughts of the witches' prophecies and begins to contemplate the idea of killing King Duncan to seize the throne. The temptation to fulfill the prophecies starts to take hold of Macbeth's mind, setting in motion the tragic events that follow.
Macbeth hesitated to harm King Duncan because Duncan was his kinsman and guest, which violated the societal codes of hospitality and loyalty. Additionally, Macbeth was also loyal to the king and had recently been honored by him, which made the idea of killing him even more unthinkable for Macbeth.
Macbeth's world keeps on getting more and more frightening. He thought he would make himself feel safe by killing Banquo. The result was a visit from a supernatural spectre. He has no idea what to do, and hopes that the witches will give him knowledge using which he can get out of this frightening world.
Lady Macbeth [b. c. 1015] was more responsible than Macbeth [c. 1014-August 15, 1057] for the plot against their sovereign, King Duncan I [d. August 14, 1040] of Scotland. In Act 1 Scene 7, Macbeth said that he didn't want to go through with the murder. Lady Macbeth countered with a fail-safe plan of killing the King and his two royal guards with the latters' own daggers. She also suggested serving drugged drinks to the guards. The King's defenders thereby would be disabled, and stopped from protecting their sovereign and themselves from the Macbeths.