After Paul spoke about the scope of God’s grace in Romans 5:18-19 – making it clear that God’s righteousness will one day reach all people – he explains the same idea again from a slightly different perspective. Because there were also many Jews in the church in Rome, the apostle takes up again with the Mosaic law.

“But the law came along by the way, that mortification might increase. But where sin increases, grace overflows, so that just as sin reigns in death, so also grace may reign through righteousness to eternal life through Jesus Christ our Lord.”
Rom 5:20-21

Here Paul once again puts the overflowing grace on display. Perhaps there would be some among the Jews in the community who held the Mosaic Law in high esteem. Paul does as well, however he does not consider the law to be the solution. Rather, he already wrote in Rom 3:21: “But now, separated from the law, God’s righteousness has been revealed …”. Why did the law come now, was it not a solution after all? Here’s what he says:

“But the law came along by the way, that the mortification might increase.”
Rom 5:20

So that was the task of the law: the grievance should increase. No salvation from following the law therefore, but an emphasis on the problems. Earlier, the apostle mentioned: “Through the law comes only knowledge of sin” (Rom 3:20). Paul comes back to this later in chapter 7. Here in Romans 5, however, his point is not to emphasize mortification or sin, but to draw out a contrast with grace. This contrast is central to the statement.

The law showed transgression. When mortification increases, sin also increases. If we speak simplistically of “sins” instead of “sin,” we realize that sins accumulated. If grace were to effectively confront the many sins, grace would logically have to be much greater. That is why Paul wrote, “But where sin increases, grace overflows” (Rom 5:20). It is about the greatness of grace. But all of this has a goal:

“That just as sin reigns in death, so also grace may reign through righteousness unto eonian life by Jesus Christ our Lord.”
Rom 5:20-21

Grace is not to be a puny solution, but grace is to reign through righteousness. This reigning is shown in the fact that aeonian life is forgiven through Jesus Christ, our Lord. This is no small matter. It affects all people, both those who believe today and those who do not believe today. That is the goal. Grace shall reign until all once attain to the righteousness of life. When this happens is not an issue here. Paul just wants to make it clear where we are going. This future is characterized by justice, grace and life for all people.

“Accordingly, as by the one grievance there came to condemnation for all men, so also by the one judgment there comes to justification of life for all men.”
Rom 5:18

This comprehensive justification of life is elaborated only a little further in Rom 5:20-21. There, too, it’s about the whole picture, because the context makes it so. “Eternal” or rather “aeonian life” is thus in prospect for all people.

“So also let grace reign through righteousness unto eonian life by Jesus Christ our Lord.”
Rom 5:21