What reason does Macbeth give for not going and killing Banquo himself?Macbeth hands the dirty work to the murderers, but what is it that stopped him from proceeding with the murder himself?
In Act III Scene 1 of Macbeth by Shakespeare, Macbeth is told by Banquo that he has all the titles now as the witches have predicted, but he also says,
...and I fear
Thou play'dst most foully for 't.
Yet it was said'It should not stand in thy posterity,
But that myself should be the root and father
Of many kings.... (3.1.2-5)
When Banquo says that he expects to have the propheses of the "weird women" come true for him, Macbeth in fear determines that
To be thus [King]is nothing, but [unless] safely thus
Our fears in Banquo stick deep. (3.1.47-48)
So, in order to ensure that he will remain king, Macbeth orders the murders of Banquo and his son Fleance. He tells the murderers that he could perform the act except for the fact that he and Banquo have mutual friends, friends who Macbeth must court for they would protest the death of Banquo. So, he must hide this act from them:
...and though I could
With barefaced power sweep him from my face
And bid my will avouch it, yet I must not
For certain friends are both his and mine,
Whose loves I may not drop, but wail his fall
Who I myself struck down. And thence it is
That I to your assistance do make love,
Masking the business from the common eye
As he talks with the hired murderers, he tells them where to put themselves and expresses the urgency of their killing Banquo and his son. Also, Macbeth instructs them to be sure to perform their deeds away from the palace, remembering that he
...require(s) a clearness; and with him--
To leave no rubs nor botches in the work--(3.1.133-134)
Macbeth wants no suspicion of his being involved in the murder of Banquo and Fleance because he wishes to remain as King.