John Calvin Commentary Romans 4:9-10

"Is this blessing then pronounced upon the circumcision, or upon the uncircumcision also? for we say, To Abraham his faith was reckoned for righteousness. How then was it reckoned? when he was in circumcision, or in uncircumcision? Not in circumcision, but in uncircumcision:" — Romans 4:9-10 (ASV)

9-10. As only circumcision and uncircumcision are mentioned, some unwisely conclude that the only question is this: that righteousness is not attained by the ceremonies of the law. But we should consider what sort of men they were with whom Paul was reasoning; for we know that hypocrites, while they generally boast of meritorious works, yet disguise themselves in outward masks.

The Jews also had their own peculiar way, by which, through a gross abuse of the law, they departed from true and genuine righteousness. Paul had said that no one is blessed but he whom God reconciles to Himself by a free pardon; it therefore follows that all are accursed whose works come to judgment.

So then, this principle is to be upheld: that men are justified, not by their own worthiness, but by the mercy of God. But still, this is not enough, unless the remission of sins precedes all works, and of these, the first was circumcision, which initiated the Jewish people into the service of God. He therefore proceeds to demonstrate this as well.

We must always bear in mind that circumcision is here mentioned as the initial work, so to speak, of the righteousness of the law: for the Jews did not glory in it as the symbol of God’s favor, but as a meritorious observance of the law. And on this account, they regarded themselves better than others, as though they possessed a higher excellence before God.

We now see that the dispute is not about one rite, but that under this single observance is included every work of the law; that is, every work to which reward can be due. Circumcision then was especially mentioned, because it was the basis of the righteousness of the law.

But Paul maintains the contrary, and thus reasons: “If Abraham’s righteousness was the remission of sins (which he safely takes as granted), and if Abraham attained this before circumcision, it then follows that remission of sins is not given for preceding merits.” You see that the argument rests on the order of causes and effects; for the cause is always before its effect; and righteousness was possessed by Abraham before he had circumcision.