In Macbeth's mind there is no justification for killing Duncan. He didn't really want to do it ("We shall proceed no further in this business") and regrets it the moment it is done. In the case of Banquo, however, his reasoning has been blunted by his fear and paranoia ("My fears in Banquo stick deep."). His fear of Banquo is unfounded, but in Macbeth's mind it does provide a justification of sorts.
Because the witches said that Banquo's descendants and not Macbeth's would be kings. So even though Macbeth is king during his lifetime, it is not a lasting legacy. "If't be so, for Banquo's issue have I filed my mind; for them the gracious Duncan have I murder'd."
After committing the first murder himself, Macbeth sends out hired murderers to deal with Banquo and with Macduff's family. As a result, he does not kill the people he is really worried about: Macduff and Fleance (since it is Banquo's children and not Banquo he is to worry about)
Well its meant to be celebrating, i suppose, Macbeth's new title as king. But the pair's main aim was to act as normal as possible(considering they killed Duncan, its a challenge, and Macbeth knowing he ordered Banquo killed) but that all kinda fails when the ghost of Banquo appears to Macbeth. Hope that answers your question!
According to the Shakespearean play, Macbeth [c. 1014-August 15, 1057] envied King Duncan I [d. August 14, 1040]. In the play, the King appeared to be an older, much beloved and respected sovereign. Even Macbeth's Lady [b. c. 1015] said that she couldn't kill the King on her own because in sleep he reminded her of her father.
The rise and fall of Macbeth, a tragic hero. He first subdues a traitor in the beginning, hears witches' prophecies which implies that he will become King but his children will not take over his throne. Subsequently, he murders Duncan, as prompted by his wife, and becomes King. However, while Duncan has always been referred to in the play as the good king, Macbeth's title was always tyrant. To secure his position, Macbeth kills Banquo, for his sons were prophesized to become Kings, and hunts down his son but failed. He also killed the wife and children of Macduff, who was loyal to the two sons of Duncan. He went to the witches and was told that no one born from woman can harm him, and that he does not have to worry until the birnam wood comes to dunsidane (I might have spelt it incorrectly). Lady Macbeth becomes ill (quite mentally) from the guilt of killing Duncan and eventually she dies. Macbeth's worst fears were realized as Malcolm and Macduff's army comes to dunsidane under the cover of tree branches, therefore making it appear as though the wood is moving. Macbeth is eventually killed because Macduff was not born from a woman exactly; he was born prematurely and torn from his mother's womb. Malcolm, son of Duncan, becomes King and peace is restored to Scotland.
These are two quotes from two different scenes of Macbeth. In the first, Macbeth is thinking out loud about his plan to assassinate Banquo. Lady Macbeth overhears and asks him about it. Macbeth wants to keep his plan secret so he asks that his wife be "innocent of the knowledge" (of his plans) but not to worry because she will see that when his plan is completed (Banquo killed) that they will be better off, so she will "applaud the deed", so to say. In the second, Macbeth is anxious over his plans to kill Duncan. Lady Macbeth can see this and asks him to "sleek o'er your rugged looks". The rugged looks represent Macbeth's obvious anxiety on his face. Sleeking it over is then removing that. This way, no one will suspect that anything is wrong. If Macbeth visibly frets, he will put his guests, including Duncan ill at ease. The more relaxed everyone is, the easier it will be for Macbeth to assassinate Duncan.
Macbeth is saying this as he thinks aloud about his plan to kill banquo and his son fleance. Lady Macbeth over hears and asks him about it. He asks her to be innocent of the knowledge but to not worry because once the deed is done she will be better off.
Both Macbeth and Lady Macbeth worry about it. She says, "Why did you bring the daggers from the place?" when Macbeth fails to leave them there. She wants them left to incriminate the guards. But Macbeth worries that they may not incriminate the guards enough, so he kills them.
He pretty much says as much in his soliloquy in Act III Scene 1. "To be thus is nothing, but to be safely thus." The murder plan has resulted in his being king all right, but he is so worried and nervous that someone will try to kill or overthrow him that there is no joy in his being king. He believes, in so far as he is rational about it, that by killing people, he can make himself feel safe. And of course the more he kills, the more people have reason to kill him. He is like an alcoholic who drinks so that he won't worry about being an alcoholic.
Lady Macbeth's plan was that Macbeth would murder Duncan, nobody would ever blame him or her, and they could happily be king and queen and she could throw lots of fancy dinner parties. What goes wrong is that Macbeth is driven crazy by guilt, becomes a paranoid loner, and wrecks the dinner parties by screaming at ghosts nobody can see. As she says: "Nought's had, all's spent, when desire's had without content". In other words it has turned to ashes in her mouth. Worse, Macbeth's paranoia and craziness has made him do things which will make people suspect him. This makes Lady Macbeth worry constantly that the murders will be brought home to them, which ironically makes her crazy and makes her spill the beans while sleepwalking. But she cannot correct her error. Duncan is dead; he cannot come out on's grave.
She is trying to encourage Macbeth, who has been acting very strangely since killing Duncan. She says, "a little water clears us of this deed" implying that once the blood is washed off, they need never worry about the murder again. This is an ironic foreshadowing of the sleepwalking scene.
who didn't go to banquet which makes Macbeth woory about a plan againts him.