Do you mean in Macbeth's soliloquy regarding Banquo or Banquo's soliloquy regarding Macbeth?
Here's Macbeth's soliloquy:
To be thus is nothing;
But to be safely thus.--Our fears in Banquo
Stick deep; and in his royalty of nature
Reigns that which would be fear'd: 'tis much he dares;
And, to that dauntless temper of his mind,
He hath a wisdom that doth guide his valour
To act in safety. There is none but he
Whose being I do fear: and, under him,
My Genius is rebuked; as, it is said,
Mark Antony's was by Caesar. He chid the sisters
When first they put the name of king upon me,
And bade them speak to him: then prophet-like
They hail'd him father to a line of kings:
Upon my head they placed a fruitless crown,
And put a barren sceptre in my gripe,
Thence to be wrench'd with an unlineal hand,
No son of mine succeeding. If 't be so,
For Banquo's issue have I filed my mind;
For them the gracious Duncan have I murder'd;
Put rancours in the vessel of my peace
Only for them; and mine eternal jewel
Given to the common enemy of man,
To make them kings, the seed of Banquo kings!
Rather than so, come fate into the list.
Banquo's soliloquy is:
Thou hast it now: king, Cawdor, Glamis, all,
As the weird women promised, 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. If there come truth from them--
As upon thee, Macbeth, their speeches shine--
Why, by the verities on thee made good,
May they not be my oracles as well,
And set me up in hope? But hush! no more.
Macbeth's soliloquy, after Duncan's murder, reveals his paranoia about the witches' predictions for Banquo. He fears that Banquo will be "greater than" he: "There is none but he / Whose being I do fear: and, under him, / My Genius is rebuked." Macbeth is also worried about Banquo's progeny, that he will father kings. Macbeth, who has so children, fears children throughout the play: first Banquo's, and then "none of woman born" (Macduff). In the soliloquy we hear Macbeth's resolve to kill Banquo and his son Fleance.
Banquo's soliloquy reveals his fear that Macbeth has "play'dst most foully for't": that he has used foul means to attain the crown. Now, he wonders if the witches' prophecies are indeed true regarding him. This is a kind of guarded hope. Banquo knows that the two sets of prophecies are intertwined, as are his hope and fear in them.