Historically, if you think of the time of Jesus, the apostles and the Roman Empire. Paul among the apostles was a Roman citizen, so he could ask for things that the others couldn't.
Those who possessed such a status enjoyed a wide range of privileges and protections which varied over time and place. Some of the more common d benefits were the right to vote in assemblies and to be eligible to run for civil or public office. It also included the right to make legal contracts or hold property, as well as the privilege of immunity from some taxes and legal obligations.
Roman citizens had the right to sue (and be sued) in the courts and the right to have a legal trial where they could appear before a proper court to defend themselves. They even had the ability to request Caesar himself hear their case.
Additionally, citizens could not be tortured or whipped (scourged), nor could they receive the death penalty, unless they were guilty of treason.