Answer:
The relationship between Macbeth's words and that of Duncan's sons is that Macbeth fakes his sadness about Duncan's death, where his sons do not, they simply go on with business, preparing to take their father's place. Though Macbeth lies, performing as a man who feels great sorrow, and Duncan's sons choose to do the opposite, and allow their actions to be perceived as silent grief, they have something in common—none of those men feel the sad about Duncan's death, for they have all gained something great from it.