Romans, The Righteousness of God Revealed Part 1: Beloved and Saint
Romans 1:5-7 "through whom we have received grace and apostleship to bring about the obedience of faith among all the Gentiles for His name's sake, among whom you also are the called of Jesus Christ;
to all who are beloved of God in Rome, called as saints: Grace to you and peace from God our Father and the Lord Jesus Christ."
When the Apostle Paul wrote to the church of Rome, he hadn't yet been there in person, so his introduction of himself and the way he chose to greet them had to be specific.
We can glean much light from the first seven verses in Romans chapter one.