Yes, again there is a sense of dramatic irony here. Banquo tells Macbeth of the King's good nature and favour towards Macbeth.
a) He could be attempting to persuade Macbeth to stay loyal.
b) He could be speaking his mind and just making small-talk.
c) He could be reminding Macbeth of the King's good character since he anticipates Macbeth's murderous intent.
Whatever is going through Banquo's mind, it is clear that this does not help Macbeth make up his mind. Banquo's words mimic Macbeth's earlier monologue where he says of the King: "I am his kinsman and his subject". He also noted that Duncan, "hath been so clear in his great office." Lady Macbeth subsequently persuades him to change his mind and to kill the King, but here Banquo's words remind Macbeth of the alternative view - that he has no right to kill such a decent and honourable man.
As the audience, we know that Macbeth is malleable (look it up) and that this could throw Macbeth back into confusion.