How do other characters reactions to Macbeth actions create an emotional impact on the audience?

Specifically to Act 4 sc 3, Macbeth isn't too popular in Scotland anymore. Macbeth is killing anyone he thinks are in his way. Macduff sums things up by saying:

Ross arrives from Scotland and reports that the country is in a shambles. When Macduff asks how his wife and children are faring, Ross first responds that they are “well at peace” (180). When pressed further, he relates the story of their death. Macduff is stunned speechless and Malcolm urges him to cure his grief by exacting revenge on Macbeth. Macduff is overcome with guilt and sorrow from the murders that occurred while he was absent. Again Malcolm urges him to put his grief to good use and seek revenge. All three men leave to prepare for battle.