Protestants consider 2 Corinthians 5:21 to be one of the chief Biblical proof texts for for their doctrine of the Imputed Righteousness of Christ. In fact, they put so much emphasis on this verse that a lot of their credibility hangs on it. Given this, I want to provide Catholics with some key information on what to say when speaking with a Protestant on this crucial text, because if you can stop them in their tracks here, you'll have gone a long way towards causing them to rethink everything about their own position and what Catholicism has to offer them.
Before examining the verse though, a Catholic must know what the Protestant understands this verse to be saying. The standard Protestant interpretation of 2 Corinthians 5:21, espoused by even the greatest Reformed theologians, can be summarized as follows (in my own words):
Our sin was imputed to Christ, "making Him to be sin," while on the other hand Christ's perfect obedience was imputed to us, "making us the righteousness of God." Given the option between Imputation and Infusion, we know that since Christ wasn't literally made sin, we can certainly say sin wasn't infused into Him, which thus makes imputation the only acceptable interpretation. Plus, in the immediate context Paul says God did not impute our sins to us (2 Cor. 5:19), indicating that God must have imputed our sins to somewhere else, namely to Christ's account. Having established the framework of imputation in Paul’s lesson, we can say that just as Jesus "becomes sin" (by imputation), the parallel must also hold true, namely that we "become the righteousness of God" in the same way (by a second imputation, received by faith alone). Here, in one concise verse, Paul is clearly describing a "double-imputation" going on, or a "Great Exchange" as many Protestants fondly refer to it. This is the essence of the Reformation teaching on Justification by Faith Alone.
The logic being employed here makes sense (for the most part), but the exegesis (i.e. interpretation of the verses) is simply poor. Here are some reasons why this typical Protestant interpretation simply doesn't work and what the correct understanding should be:
First, the text does not suggest we become righteousness in the same way Jesus becomes sin, i.e. by a double imputation, because Paul uses two different Greek words here, "made [sin]" and "become [righteousness]". This detail is significant, and we cannot be sloppy by inserting "made" in both cases. By using two different terms, both of which suggest transformation rather than imputation, Paul most likely was indicating the 'transformations' take place two different ways. Thus, grammatically speaking, there is no 'parallelism' going on here, and thus assuming this text is speaking of a double-imputation is uncalled for. Rather, Paul is describing a cause-and-effect situation: by Christ doing X for us, this caused Y in us.
Second, the curious phrase "made sin for us" cannot be presumed to include Christ's perfect obedience to the Law, especially since the Protestant says this phrase refers specifically to having our sins imputed to Christ. In other words, nothing about the words “made sin for us” suggests a double imputation, but at most a single imputation (i.e. only our sin imputed to Him). This is important, because for the Protestant position to hold true, it’s not enough that Christ dealt with our sin, for that would only put us back to the ‘innocent’ position of Adam. Instead, Protestants say Christ also had to keep the Law perfectly in our place, and impute this perfect obedience to us (causing us to “become the righteousness of God”), so that we then can be reckoned as having perfectly kept the Law and thus worthy of entering Heaven. The phrase “made sin for us” simply cannot be twisted to include Christ keeping the Law on our behalf. Now Christ certainly had to be perfectly obedient (i.e. without sin) to become a perfect sacrifice, but according to the wording it's only the suffering for our sins that caused (resulted in) us to become “the righteousness of God.” (See my many articles regarding "Active Obedience" for more information on this point.)
Third, the Bible never speaks of imputing sin from a sinner onto an innocent substitute, such that guilt is transferred from one person to another, so to say “made sin” refers to imputation has no Biblical basis whatsoever. Thus, Christ being “made sin” must be assumed to refer to something other than imputation. The term impute (logizomai in Greek, which I've written about a lot) is used numerous times in Scripture but never is it used to refer to sins being imputed to an innocent substitute, even in the Levitical Sacrifices. This fact alone undermines the Protestant reading, since they've "gone beyond what is written" (1 Cor 4:6) and substituted a tradition of men in place of God's Word. The few references to “imputing sin” mentioned in Scripture are stated in the negative, each saying sin is “not imputed” to a person, e.g. 2 Corinthians 5:19 and Romans 4:7-8 (more on these texts later). Also, nothing about “not imputing sin” logically necessitates nor suggests the Protestant fallacy that ‘if sin is not imputed to us, then it must be imputed to someone else’, so this Protestant claim holds no water at all.
Fourth, the meaning of “made sin” need not only refer to Imputation or Infusion, for that’s a false dilemma fallacy. The Church Fathers shed valuable light on what “made sin” refers to. Many Catholics are aware that some Fathers claimed that “made sin” refers to being “made a sacrifice for sin,” since the Hebrew word for “sin” doubled in the Old Testament as a term referring to personal failings as well as Levitical Sacrifices. Scriptural support for this “sin offering” claim not only includes many texts of Leviticus, but even New Testament texts like Hebrews 10:5-8; 10:18; and 13:11, where the Greek term “sin” (hamartia) is used but is clearly referring to a “sacrifice for sin” and not personal failings. In Hebrews 10:6, it is directly quoting Psalm 40:6-8, an OT text speaking of sacrifices of various types, saying: “In burnt offerings and sin offerings [hamartia] you have taken no pleasure.”
There is a slight catch though, because the texts where the Greek word hamartia (sin) is rendered as “sin offering,” it most often uses a special form, peri hamartias (“for sin”=sin offering), whereas 2 Corinthians 5:21 simply uses hamartia (without the “peri” or the –s). The only possible exceptions I’m aware of where ‘hamaria’ alone could refer to “sin offering” are Leviticus 4:21b, Leviticus 4:24b, and Leviticus 5:12b, where most translations do render ‘hamartia’ as ‘offering for sin’ in English. But fortunately that’s not the whole picture.
The Church Fathers whom I was able to find commenting on 2 Corinthians 5:21 formed a general consensus on what “made sin” referred to. Consider:
Augustine: "on account of the likeness of sinful flesh in which He came, He was called sin" (Enchiridion, Ch41)The 'consensus' among the Fathers on the meaning of "made sin" in 2 Corinthians 5:21 is that it refers to "the Word was made flesh," the Son becoming Incarnate, which is also why they also linked 2 Corinthians 5:21 directly to Romans 8:3, "By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh." Using the principle of Scripture-interprets-Scripture, that's what "made sin" means, and it's not hard to see.
Augustine: "For God made Christ Himself to be sin for us, on account of the likeness of sinful flesh, that we may be made the righteousness of God in Him." (Commentary on Psalm 119, Ain, Section 122)
Gregory Nyssa: "He made Him to be sin for us, Who knew no sin,” giving once more the name of “sin” to the flesh." (Against Eunomius, Book 6, Section 1)
Gregory of Nazianzen: "And so the passage, The Word was made Flesh, seems to me to be equivalent to that in which it is said that He was made sin." (Letter To Cledonius [Epistle CI])
Hilary: “To condemn sin through sin in the flesh, He Who knew no sin was Himself made sin; that is, by means of the flesh to condemn sin in the flesh, He became flesh on our behalf but knew not flesh” (On the Trinity, Book 10, Section 47)
Ambrose: “Christ is said to have been made, but of a woman; that is, He was “made” as regards his birth from a Virgin … He Who in his flesh bore our flesh, in His body bore our infirmities and our curses … So it is written elsewhere: Who knew no sin, but was made sin for us” (Against Auxentius, Section 25)
Pope Leo the Great: "When the evangelist says, “The Word became flesh and dwelt in us,” and the Apostle, “God was in Christ reconciling the world to Himself,” it was shown that the Only-begotten of the Most High Father entered on such a union with human humility, that, when He took the substance of our flesh and soul, He remained one and the same Son of God." (Sermon LXIII.1)
But there is a 'bonus' here that need not be ignored either, and that is the words "and for sin" which immediately follows is the Greek phrase peri hamartias (περὶ ἁμαρτίας), the very phrase mentioned earlier, which does indeed refer to "sin offering"! So both realities, Incarnation and sin offering, are certainly present, even if the Incarnation is the more central.
Fifth, the context clearly explains the goal of God the Father sending His Son was to bring about our reconciliation, thus undermining the whole presumed forensic-imputation theme Protestants project onto verse 21. Verse 5:20 explains that Paul is an ambassador of Christ, calling us to be "reconciled to God." So the focus here is on "reconciliation," which is the restoring of a broken friendship. (Cf 1 Cor 7:10-11) This isn't really a forensic category, for the defendant doesn’t reconcile with the Judge in a courtroom. This also strongly goes against an "imputation of Christ's Righteousness" theme, because reconciling is about restoring what was lost, not supplying something new that was never possessed. The implication is that we are restored to communion with God as Adam was originally in communion, otherwise there’s no reference point of a relationship break requiring reconciliation. And verse 5:19 is just as helpful, for it tells us that this reconciliation was done by “not imputing their sins,” which refers to forgiving sin since Romans 4:7-8 use ‘not impute sin’ in that very manner. Using context as a guide, it’s reasonable to conclude that “becoming the righteousness of God” must refer to being reconciled to God and having sins forgiven. Otherwise, “becoming the righteousness of God” refers to something not spoken of within the immediate context, which is unlikely. And this is confirmed when we examine a parallel text, Romans 5:9-10, where the phrase "justified by his blood" is paralleled to "reconciled by his death".
In conclusion, we see that the Protestant interpretation is clearly ruled out given (a) the terminology Paul chose to use, (b) the logic structure of the verse, and (c) the context. In turn, we see that the Protestant side has to desperately cling to this verse and pile upon it all sorts of bogus assumptions because there simply is no other clear proof of their teachings in Scripture. The fact is, the Bible is a Catholic book and Paul was thoroughly Catholic in his teachings.
Please see This Recent Post from Jason Stellman's blog which also briefly discusses this issue.
Please see This Recent Post from Jason Stellman's blog which also briefly discusses this issue.