what does banquo suggest about macbeth's reaction to the witches prophecy?

Banquo notices that Macbeth is lost in thoughts about what the witches said, "Look how our partner's rapt." Banquo later warns Macbeth not to trust witches. They will tell him good things only to betray him in the end,

"The instruments of darkness tell us truths,. Win us with honest trifles, to betray 's. In deepest consequence."