The conversation between Macbeth and Banquo in Act 2, Scene 1 of Shakespeare's Macbeth is marvelous in its subtlety. The two men are talking about something and pretending they are not really talking about it. Macbeth begins this heavily guarded conversation by saying, "I think not of them" (i.e., the Weird Sisters),

Yet, when we can entreat an hour to serve,
We would spend it in some words upon that business,
If you would grant the time.

There would never be a better time than right now. They are alone. It is late at night. Both are wide awake. But Banquo does not ask, "What do you have in mind?" or anything like that. Very characteristically prudent and self-contained, he says:

At your kindest leisure.

If Macbeth wants to talk about the Weird Sisters, he obviously wants to talk about their predictions that he will become king and that Banquo will sire a whole line of kings. Macbeth makes it pretty clear that he wants to talk about the two of them cooperating in a coup against Duncan when he says:

If you should cleave to my consent, when 'tis,
It shall make honor for you.

They are still talking about having some talk at some future time, but the talk is already over when Banquo says:

So I lose none
In seeking to augment it, but still keep
My bosom franchised and allegiance clear,
I shall be counseled.

Which is the same as saying, "I know what you have in mind, and I want no part of it."

Macbeth dismisses Banquo along with the proposal he has in mind with the ominous words:

Good repose the while.

This could be taken as a threat as well as a way of saying, in effect, "Forget it! I can get along without you." There will be no future conversation about what they have pointedly not been talking about.

Something strikingly and amusingly similar takes place in David Mamet's wonderful contemporary play Glengarry Glen Ross. Dave Moss is sounding George Aaronow out about staging a fake robbery at the real estate office, stealing the Glengarry Glen Ross leads, and selling them to a competitor named Graff.

AARONOW
Yes. I mean are you actually talking about this, or are we just . . .

MOSS
No, we're just . . .

AARONOW
We're just "talking" about it.

MOSS
We're just speaking about it.
(pause)
As an idea.

AARONOW
As an idea.

MOSS
Yes.

AARONOW
We're not actually talking about it.

MOSS
No.

AARONOW
Talking about it as a . . .

MOSS
No.

AARONOW
As a robbery.

MOSS
As a "robbery"?! No.

It has been suggested that Macbeth probably wanted Banquo's help because he would have liked to kill Duncan's two sons that same night. When Madbeth is forced to act alone, he is unable to dispose of Malcolm and Donalbain because he loses his nerve and imagines he hears a voice cry:

"Sleep no more!
Macbeth does murder sleep"
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
"Glamis hath murdered sleep, and therefore Cawdor
Shall sleep no more. Macbeth shall sleep no more."

There is a very short dialogue between Macbeth and Banquo in this scene which is interesting for a number of reasons. Let us remember that this is the first time that Banquo and Macbeth have had chance to speak to each other since their meeting with the witches, and since then some of the prophecies that the witches made concerning Macbeth have come true. The only one that has yet to materialise is the prophecy that Macbeth will become King of Scotland. This is the unspoken fact that lies between Macbeth and Banquo, and even when Banquo tries to raise this issue, Macbeth responds in a way that does not encourage further conversation, saying, on the one hand, "I think not of them," but then going on to say that they should meet to discuss this further. Note what Macbeth says to Banquo:

If you shall cleave to my consent, when 'tis,

It shall make honour for you.

Banquo's response, in which he refers to keeping his "alegiance clear" and his "bosom franchis'd" clearly points towards the treasonous intent he sees in Macbeth's words, and there is something very suspicious in the way that Macbeth one moment protests that he does not think of the witches and their prophecy only then to suggest a secret meeting with Banquo the next moment.