Paul is the apostle of the Gentiles, not Calvin or Luther or any Reformed person.
For I speak to you Gentiles, inasmuch as I am the apostle of the Gentiles, I magnify mine office: - Rom 11:13
That is why I read and study Paul's letters so much.
Watch out for deception from Calvin's or Luther's or Reformed writings.
Remember:
1 Would to God ye could bear with me a little in my folly: and indeed bear with me.
2 For I am jealous over you with godly jealousy: for I have espoused you to one husband, that I may present you as a chaste virgin to Christ.
3 But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ.
4 For if he that cometh preacheth another Jesus, whom we have not preached, or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him.