The Apostle Paul
Romans 1:5ESV·traditional attribution

through whom we have received grace and apostleship to bring about the obedience of faith for the sake of his name among all the nations,

John Calvin Reformed @genevareformer

5. Through whom we have received, etc. — Having completed his definition of the gospel, which he introduced for the recommendation of his office, he now returns to speak of his own call; and it was a great point that this should be proved to the Romans.

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

By whom we have received grace and apostleship,.... That is, either by the Holy Spirit, from whom all grace and gifts come, qualifying for the discharge of any office; or by the Lord Jesus Christ, who is full of grace and truth, has received gifts for, and gives them to men to fit them for whatsoever service he is pleased to call them to.