Here are some comments on Romans 4 and James 2 that should help you:
commenting on Romans 4:10-11, “How then was it accounted? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised. And he received the sign of circumcision, a seal of the righteousness of the faith which he had while still uncircumcised, that he might be the father of all those who believe, though they are uncircumcised, that righteousness might be imputed to them also,”
Paul, knowing that his opponents will still want to say that in some way Abraham’s works formed at least a part of his justification before God, rules that out in this verse. Abraham was justified by faith before he was circumcised. This will be a critical statement for my opponent to deal with, for if he says (as all Roman Catholics I have dialogued about this with have) that James chapter two is teaching that Abraham was ‘justified’ in exactly the same sense (when he offered Isaac) as Paul does here, we are faced with a diametric contradiction to Paul’s express teaching in this passage. When Paul offered Isaac in Genesis 22, that was years after he was circumcised. Paul leaves no room for doubt about when Abraham was justified before God, “not while circumcised, but while uncircumcised.” That is, in my opinion, the ultimate problem with the standard Roman Catholic interpretation of James 2:24. The standard Roman Catholic interpretation of James chapter two hands the victory to Paul’s enemies.
To preclude the most common Roman Catholic response I’ve heard to this point, I’ve included this little paragraph. Most Catholic apologists will argue that Abraham was actually justified before God in exactly the same way in both instances, i.e. when he believed the promise of Yahweh in Genesis 15:6 and also in Genesis 22 when he was about to offer up Isaac as a burnt offering. Were this the case, Paul simply could not have argued the way he does in Romans chapter 4. If Abraham were justified before God more than once, i.e. once before his circumcision and again after his circumcision, this would have been a rather devastating reason not to argue so vociferously in these words, “How then was it accounted? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised.” If Paul’s enemies could simply have said, “Well Paul, it was both before and after,” his entire argument against works playing a role in justification, against circumcision playing a role in justification, that God justifies the ungodly, and that God justifies the one who believes by imputing righteousness to them apart from works would have no merit whatsoever. If Abraham was justified before God after he was circumcised, Paul seems to have been utterly unaware of it – and such would be impossible for here Paul is expositing the precious doctrine of justification in a book of inspired Scripture.
BouleTheou