What is the theme of the story

Mr and mrs van daan murmur their welcome what are the playwrights indicating by using the word murmur?

[v]ast numbers of our people are compelled to seek their livelihood by begging, robbing, stealing, cheating, flattering, suborning, forswearing, forging . . which satirical element is most dominant in the passage above?

Lines 47–56: determine the central idea of these lines