This is one of the more interesting questions that emerges from Macbeth, because it directly addresses one of the play's important themes, i.e. individual responsibility in determining one's own fate. The plot was, of course, Macbeth's idea to begin with. But in his soliloquy at the beginning of Act I, Scene 5, he is torn over whether to do something he knows is wrong, and fears that the consequences of such a bloody deed will come back on him:
This even-handed justice
Commends the ingredients of our poison'd chalice
To our own lips.
By the end of his speech, as Lady Macbeth walks in the room, he clearly says that he will not commit the murder, at least not then:
We will proceed no further in this business:
He hath honor'd me of late, and I have bought
Golden opinions from all sorts of people,
Which would be worn now in their newest gloss,
Not cast aside so soon.
At this point, Lady Macbeth castigates him, questioning his integrity, his courage, and ultimately his masculinity in order to persuade him to carry out the murder. Macbeth is steeled to the task, and Duncan's fate is sealed. So it seems that while Macbeth could always have schemed to murder Duncan later, he was no longer planning on doing it in his castle until Lady Macbeth talked him into it.
Through my opinion I would suggest that macbeth would not had committed the by the encouragement of lady macbeth because he was the one testing macbeth's manliness and calling him coward and insulting his manlines nature. Macbeth feels that he this a sin and he says "we should procede no further in this business". Macbeth knows that he is duncan's subject who should work and honour, then as a host who should shut the door to the evil not bear the sword himself and the he thinkd of duncan as his relative and duncan is a person who is full of piousness and generousness. So seeing these things macbeth decides to go away from doing this deed but only because of lady macbeth and encouragement and insult to macbeth' bravery does persuade macbeth again to the evil deed.