We hear, our bloody cousins are bestow'd in England & Ireland, not confessing their cruel parricide.
Act 3, Scene 1
They hail'd him father to a line of kings: upon my head they placed a fruitless crown.
Act 3, Scene 2
Better be with the dead, whom we, to gain our peace, have sent to peace, than on the torture of the mind to lie in restless ecstasy.
Banquo harbours some suspicion to Macbeth and so Macbeth fabricates the truth to influence him to suspect the wrong people. (III.i.1-3) (III.i.33-35)
Act 3, Scene 3
Thou hast it now: king, Cawdor, Glamis, all ... I fear thou play'dst most foully for't.
Macbeth is angry in this scene about the witches prophecies. He now sees Banquo and his future sons as a threat to his stolen kingship. (III.i.64-65)
Act 3, Scene 4
Here had we now our country's honour roof'd, were the grac'd person of our Banquo present.
Lady Macbeth believes that he is only talking about the guilt of Duncan, while he had planned the murder of Banquo in the scene before (dramatic irony). Macbeth continues to express guilt in his actions and thoughts but does not seem to realize it. (III.ii.21-24)
Act 3, Scene 4
Thou canst not say I did it: never shake thy gory locks at me.
This scene truly shows the lengths that Macbeth is willing to go to; killing his supposed best friend. However, Fleance escapes, rendering his plan useless. (III.iii.25) (III.iii.30-31)
We have lost best half of our affair.
Macbeth addresses his guests saying that Banquo has ruined the unity at the banquet. Macbeth, however, knows that Banquo is already dead (dramatic irony). (III.i.130-131) (III.iv.49-50)
I could with barefaced power sweep him from my sight.
Macbeth sees a ghost of Banquo at the banquet and has many loud outbursts in front of his guests. These hallucinations are subconsciously fabricated through Macbeth's remorse, and yet he does not understand them. (III.iv.63-64) (III.iv.74-75)
O proper stuff! This is the very painting of your fear.