Acts 24

 Paul must have been a skilled and gifted speaker explaining to Felix - 

"...Touching the resurrection of the dead I am called in question by you this day.

22 And when Felix heard these things, having more perfect knowledge of that way, he deferred them, and said, When Lysias the chief captain shall come down, I will know the uttermost of your matter.

23 And he commanded a centurion to keep Paul, and to let him have liberty, and that he should forbid none of his acquaintance to minister or come unto him.

24 And after certain days, when Felix came with his wife Drusilla, which was a Jewess, he sent for Paul, and heard him concerning the faith in Christ.

25 And as he reasoned of righteousness, temperance, and judgment to come, Felix trembled, and answered, Go thy way for this time; when I have a convenient season, I will call for thee."  (Acts 24:21–25)

It is interesting that this went on for two years until Felix was replaced by Festus.