Romans 2 isn't about losing salvation, what Paul discusses for nearly three chapters is the need for salvation.
Or do you show contempt for the riches of his kindness, forbearance and patience, not realizing that God’s kindness is intended to lead you to repentance? (Romans 2:3)
Who are you to judge someone else or do you have so much contempt for the grace of God? When you judge another you are condemning yourself.
For God does not show favoritism. All who sin apart from the law will also perish apart from the law, and all who sin under the law will be judged by the law. (Romans 2:11,12)
The church in Rome was Jewish originally, converted at Pentecost. There was a serious division in the early church when the Samaritans and then the Gentiles were included. At Jerusalem the Pharisees argued that Gentiles must be circumcised in order to be saved, Peter stood up and argued that neither 'we' (the Jews), nor our fathers,could bear the yoke of the Mosaic Law. Further he argues that the Gentiles are purifying themselves by grace through faith. Justification by grace through faith isn't uniquely Pauline and it didn't originate in the Protestant Reformation, it's the Apostle's doctrine period.
By now at Rome they are well aware of the mission to the Gentiles in Cyprus, Galatia Asia Minor and Greece. They are living in profoundly pagan culture and struggling with the inclusion of the Gentiles into the covenants and promises of Israel. Paul is arguing that there is no difference, Jews are sinners saved by grace and that redemption is being offered to Gentiles who can receive it by faith, apart from works.
So far the thread appears to be set up as a strawman, a version of Calvinism that simply does not exist. Neither John Calvin nor any traditional Calvinists have taught that you can live like the devil and still be saved. What they have always taught is that salvation starts with justification, apart from works of the Law or any human agency or self will. Further they have always taught that sanctification must necessarily follow.
Paul was slandered for his preaching of grace:
However, if my falsehood accentuates God’s truthfulness, to the increase of His glory, why am I still condemned as a sinner? Why not say, as some slanderously claim that we say, “- Let us do evil that good may result?” Their condemnation is deserved! What then? Are we any better? Not at all. For we have already made the charge that Jews and Greeks alike are all under sin (Romans 3:7-9)
Peter, the Apostles and all true ministers teach that we are saved by grace apart from works. What is the problem with eternal security? Is there another kind of security through faith in the gospel, what's the alternative, temporary security?
I will no longer be in the world, but they are in the world, and I am coming to You. Holy Father, protect them by Your name, the name You gave Me, so that they may be one as We are one. While I was with them, I protected them and guarded them by Your name, the name You gave Me. Not one of them has been lost, except the son of destruction, so that the Scripture would be fulfilled. (John 17:11,12)
What is the mark of a disciple?
By this everyone will know that you are my disciples, if you love one another.” (John 13:35)
Calvinists do not now nor have they ever taught that you need not bear fruit, the insinuation is slanderous. Grace not only saves us but sanctifies us, apart from Christ we can do nothing and to make myself clear, your merit counts for nothing. If one were to ask the Apostle Paul how it is that he worked so hard and suffered so much and bringing so many the Gospel, he would, and did, tell us that it is by grace.
But by the grace of God I am what I am, and his grace to me was not without effect. No, I worked harder than all of themyet not I, but the grace of God that was with me. (I Cor. 15:10)
A good working definition for grace is 'unmerited favor', Paul worked in the ministry field by grace alone and he is crystal clear on this point. The merits of Christian ministry are Christ's alone we can add nothing. James in speaking to believers who were obviously showing favoritism was simply telling them that this is not how saving faith works. He was outraged that a wealthy Christian could teach a poor Christian as inferior when they themselves apart from Christ are poor, pitiful, blind and naked. We will receive that full recompense of righteousness and be glorified forever based on Christ's merit, it is never our own.
Calvin never said that nor do I, nor would any self respecting Calvinist would deny that we are to love God with all our heart, mind, soul and strength and our neighbor as ourselves.
For we maintain that a person is justified by faith apart from the works of the law. (Rom. 3:28)
Did that which is good, then, become death to me? By no means! Nevertheless, in order that sin might be recognized as sin, it used what is good to bring about my death, so that through the commandment sin might become utterly sinful. (Rom. 7:13)
The law convicts us of sin, grace saves us from it.
Grace and peace,
Mark