All of … Judea: John the Baptist attracted a lot of attention. Many people believed that there had been no prophet for over 400 years. So, prophets were associated with Israel's past and the future reign of the Messiah.
John preached repentance (turning away from sin and returning to God), like the ancient prophets. He also dressed like the great prophet Elijah (1:6), whom God promised would return in the last days (Malachi 4:5).