I believe that the Book of Romans talks about different groups of people and should not be used to generalise certain prooftexts to everyone. I believe that this Letter to the Romans clearly shows the division there was, in those days, between the Jewish and Gentile converts.
This is how I generally divide the Book of Romans:
Chapter 1: How all Gentile sinners (a collective group) became the group of Gentile sinners.
Chapter 2: How all Jewish sinners became the group of Jewish sinners.
Chapter 3:1-20: Why the group of Jewish sinners is not better than the group of Gentile sinners.
Chapter 3:21-5:11: How the group of Jewish sinners, can be justified by faith, just like the group of Gentile sinners.
Chapter 5:12-21: Historical explanation of how the Jewish group of sinners and the Gentile group of sinners were once one archegroup of sinners, before they got split up in the two groups of sinners. In the same way, the group of Gentile sinners and the group of Jewish sinners can now be united again, by being justified by faith, in one group of Christian saints.
Chapter 6: How that that one group of saints has been set free in Christ and does not have to sin anymore.
Chapter 7: How the part of the saints, who once belonged to the group of Jewish sinners has been set free from their guilt under the law and the consequent grip of satan, holding them in bondage to sin.
Chapter 7:14b-25: Paul tells us how he was addicted to sin (14b-24) and how Christ set him free (25, see also chapter 8:2), as a testimony to the Jewish group of sinners.
Chapter 8: He tells the group of saints (especially the Jews) that they will not be counted as guilty, if they live in obedience under Christ. He also talks about eternal security for the group of saints, if they stand their ground.
Chapter 9: Paul’s wish for the Jewish group of sinners. He hopes that the whole group of Jewish sinners will be set free in Christ, just like he and a remnant were set free.
Chapter 10: Paul’s wish for the Jewish group of sinners (cont.). The Jewish group of sinners wants to be right with God, by the works of the law and not by faith.
Chapter 11: This is what stops the group of Jewish sinners, not the grace of God. The saints who belonged to the group of Gentile sinners need to be obedient to the grace, otherwise they will be removed (by the Father).
Chapter 12: Both groups of liberated saints (formerly belonging to the group of Jewish sinners and the group of Gentile sinners) must work together in humility. They must be obedient to God [as they are now one group of saints and must act like one].
Chapter 13: They must be humble towards leaders and towards each other.
Chapter 14: The stronger believers (belonging to the group of saints) must take care of the weaker group of saints (also belonging to the group of saints).
Chapter 15: Same theme. Also contains Paul’s further journey plans.
Chapter 16: Recommendations of people and greetings to people.