As they stretched him out to flog him, Paul said to the centurion standing there, "Is it legal for you to flog a Roman citizen who hasn't even been found guilty?"1
References for Acts 22:25
When the centurion heard this, he went to the commander and reported it. "What are you going to do?" he asked. "This man is a Roman citizen."
The commander went to Paul and asked, "Tell me, are you a Roman citizen?" "Yes, I am," he answered.
Then the commander said, "I had to pay a big price for my citizenship." "But I was born a citizen," Paul replied.
Those who were about to question him2 withdrew immediately. The commander himself was alarmed when he realized that he had put Paul, a Roman citizen,3 in chains.4
References for Acts 22:29