The Jewish people hated Jewish tax collectors (Matthew 5:46–47; 18:15–20). This was because they worked with Roman rulers. Jews considered them traitors against Israel. Many also considered them ceremonially unclean because of their contact with Gentiles and the images on Roman coins.
Tax collection was a private business. In each area, Rome gave the right to collect taxes to the highest bidder (compare Luke 19:1–10). Collectors kept any money they gathered above their bid. Out of greed, they often used threats to get the money.