What does Luke 3:10 mean?

John the Baptist spent most of his life living in the desert, preparing to preach repentance (Luke 1:80). When the time came (Luke 3:1–6), his message was blunt: you cannot rely on rituals or heritage to be saved. All must sincerely repent of sin (Luke 3:7–9). In response, the people ask what to do. The messages John gives in the next verses are targeted at specific groups of people, along with their most common temptations (Luke 3:11–14).

The "crowds" here to see John are made up of independent seekers, as well as local religious leaders and their supporters (John 1:29). Much of John's harsh tone seems to be directed at these authority figures (Matthew 3:7–12). Sincere members of John's audience would want to know what, exactly, they should do in response to his message. Insincere listeners might ask the question, "what then shall we do" in a challenging way, as if to say, "what are you implying?"