Macbeth question : explain the dramatic irony of these lines of scene threelines 4-8 "each new morn  line 14 " he hath not touched you yet "line 180 "no, they were well at peace when i did leave'em "

The dramatic irony in this scene comes from the fact that Macduff and Malcolm have no idea that Macduff's whole family has been murdered. They speak of the fact that Macduff has not been "touched" yet by Macbeth and the fact that they were "at peace" when Macduff last saw them. The audience at this point would know that the opposite is true now.