Even St Paul while a tax collector and a pagan was concerned in serving the Roman State before his conversion.
Doubly
wrong!
The
tax-collector eventual saint was
Matthew the Evangelist.
Saul was
not a
pagan; he was a
Jєω, born into the tribe of
Benjamin, and received a privileged formal education in the
Pharisaic Jєωιѕн faith, attending the school conducted in
Jerusalem by the famed doctor of the Law (named)
Gamaliel (Acts 5:34 &seq., 22:3). And his father saw to it that he learned the skill of a
tent-maker (teaching one's son a mundane-but-marketable skill was reportedly a Jєωιѕн custom of that place & time). He also bore the Latin name
Paul, as a Roman citizen born in the Cilician metropolis Tarsus. At some time in adulthood, he began operating as what we might nowadays call a "
bounty hunter" or an "
enforcer" (
oy vey! ). The people that Saul sought or pursued were Jєωs who, from the Jєωιѕн perspective, were punishable as
apostates or
heretics, but whom Catholics honor as early converts to the faith identified by Greek words meaning "The Way", later known as "Christianity".
On the day that Saul had his encounter with the blinding light of Jesus, he was carrying letters of authorization or introduction from the chief priests of
Second Temple, to ѕуηαgσgυєs in Damascus, so he could expand his operations beyond those that'd made him notorious to Christians in Jerusalem (had Jerusalem gotten a wee bit "too hot" for his operations?). But he had a
biiig problem: He'd been struck blind, so he had to be led by hand to Damascus. After Saul arrived, the Lord sent him the disciple Ananias, who cured Saul's blindness and then baptized him. The eventual St. Paul began preaching Christianity, audaciously visiting ѕуηαgσgυєs there to do so. Meanwhile, Jєωs began plotting to kill Paul (Acts presents no specific reason, but a few are readily imagined). He escaped 1 plot against him in Damascus, and fled to Jerusalem. But because of the fearsome reputation he earned as Saul in Jerusalem, the Christian disciples initially refused to take the risk of meeting him, with 1 exception: The eventual St. Barnabas, a native of Cyprus (Acts 4:36), who brought Paul on visits to those original Apostles who'd remained there, and convinced various disciples of Paul's Christian conversion & bold preaching in Damascus (Acts 9).
For more of his life, see the subject article in the
Catholic Encyclopedia: <
http://www.newadvent.org/cathen/11567b.htm>.
The
C.E. article contains a terse in-line reference, but no full citation, that seems to be this book: Thomas Lewin:
Life of St. Paul, vol. 1 (London: 1874).