The Apostle Paul
Romans 1:6BSB·traditional attribution

And you also are among those who are called to belong to Jesus Christ.

Matthew Henry Presbyterian @wholebiblehenry

In this paragraph we have, I. The person who writes the epistle described (Rom 1:1): Paul, a servant of Jesus Christ; this is his title of honour, which he glories in, not as the Jewish teachers, Rabbi, Rabbi; but a servant, a more immediate attendant, a steward in the house. Called to be an apostle.

Commenting on Romans 1:1-7

John Gill Reformed Baptist @doctorgill

Among whom are ye also,.... The Romans, though they were the chief, were among the nations of the world to whom the apostles were sent; and since Paul was called to be an apostle, and had, as others, grace and apostleship, and particularly the apostleship of the uncircumcision, or was ordained a teacher of the Gentiles, more especially he was an apostle to them, and...

Albert Barnes Presbyterian @notesbybarnes

Verse 6. Among whom. That is, among the Gentiles who had become obedient to the Christian faith, in accordance with the design of the gospel, . This proves that the church at Rome was made up--partly at least, if not mainly--of Gentiles or pagans. This is fully proved in the sixteenth chapter by the names of the persons whom Paul salutes. The called of Jesus Christ.