Some Catholics and Eastern Orthodox like to say Martin Luther invented the concept of the “Great Exchange.” The Great Exchange, in short, teaches that Christ bore the punishment for our sins, thus satisfying God’s need for justice, but at the same time credited us Christ’s righteousness.
A graphic representation of what 2 Cor 5:21 amongst other Scriptures teaches about the Great Exchange.
The Scripture is abundantly clear that Chris bore the penalty for our sins:
But He was pierced through for our transgressions,
He was crushed for our iniquities;
The chastening for our well-being fell upon Him,
And by His scourging we are healed (Is 53:7).
My Servant, will justify the many,
As He will bear their iniquities (Is 53:11).
Yet He Himself bore the sin of many,
And interceded for the transgressors (Is 53:12).
When you were dead in your transgressions and the uncircumcision of your flesh, He made you alive together with Him, having forgiven us all our transgressions, having canceled out the certificate of debt consisting of decrees against us, which was hostile to us; and He has taken it out of the way, having nailed it to the cross (Col 3:13, 14).
To doubt that Christ bore our iniquities and paid their penalty on the cross, is in my mind, is completely unthinkable. Being that there are Catholic apologists that for whatever reason reject this plain statement of fact, my response to them is that this is not an idea Luther invented.
The Epistle to Diognetus, written in the second century, understood the ramifications of Christ baring the burdens of our sins, if not also crediting us His righteousness:
He Himself took on Him the burden of our iniquities, He gave His own Son as a ransom for us, the holy One for transgressors, the blameless One for the wicked, the righteous One for the unrighteous, the incorruptible One for the corruptible, the immortal One for them that are mortal. For what other thing was capable of covering our sins than His righteousness? By what other one was it possible that we, the wicked and ungodly, could be justified, than by the only Son of God? O sweet exchange! O unsearchable operation! O benefits surpassing all expectation! that the wickedness of many should be hid in a single righteous One, and that the righteousness of One should justify many transgressors (Chapter 9)!
The underlined is where we may infer that the Epistle taught the positive imputation of Christ’s righteousness. However, because it is inferred it is not convincing to Catholics or Eastern Orthodox who find it hard to believe that unrighteous men like us can really be credited fully righteous as Christ.
It is not an idea that is explicit in the Scripture. We may infer it from passages that speak of us being “in Christ” and others such as Eph 5:31-32 which speak of the Church’s literal union with Christ. The idea is, if the Church (with its believers) are literally one with Christ, they my be accounted as righteous as Christ upon judgment.
Indeed, this is an interpretative stretch, but one that appears justified by 2 Cor 5:21 which states, “He made Him who knew no sin to be sin on our behalf, so that we might become the righteousness of God in Him.” Christians are not merely made righteous or credited as righteous in a theoretical sense, but really “become the righteousness” specifically “of God” and not their own, an “alien righteousness.”
Now, Catholics and Eastern Orthodox reject this for legitimate interpretive reasons, but also because of its ramifications. If believers are in union with Christ, and this happens upon faith in Christ, then good works wrought in holiness really do not make one more righteous in any way. Instead, it is Christ’s righteousness that really makes us righteous, not us conforming or doing something in accord with Christlikeness. Hence, we can be really unchristlike, but be accounted fully as righteous as Christ due to our union with Him.
This does not mean that by necessity all Christians achieve equal awards in heaven. The Scripture mitigates against this as does the interpreters of the early church, specifically Jerome in his letters against Jovanian.
However, it does mean that our justification is a completed act because of what Christ done, not an ongoing event. Our union with Christ does not increase in time, rather it gets consummated specifically upon Christ’s second coming.
This is why Protestants teach “Forensic Justification,” which in short means that justification is a completed and not a ongoing act. We simply can point to Scripture that uses the words “believed” and “justified” in the past tense to show that the event already occurred. Catholics and Eastern Orthodox accuse of of preaching a novelty. However, let our argument be based upon the Scripture and not tradition, because we are not the first to traditionally to espouse the idea. Cyril of Jerusalem writes:
Oh the great loving-kindness of God! For the righteous were many years in pleasing Him: but what they succeeded in gaining by many years of well-pleasing , this Jesus now bestows on you in a single hour. For if you shall believe that Jesus Christ is Lord, and that God raised Him from the dead, you shall be saved, and shall be transported into Paradise by Him who brought in there the robber. And doubt not whether it is possible; for He who on this sacred Golgotha saved the robber after one single hour of belief, the same shall save you also on your believing (Catechetical Lecture 5, Chap 10).
Chrysostom concurs in his exegesis of Rom 3:26:
He does also make them that are filled with the putrefying sores of sin suddenly righteous. And it is to explain this, viz. what is
declaring, that he has added,
That He might be just, and the justifier of him which believes in Jesus. Doubt not then: for it is not of works, but of faith: and shun not the righteousness of God (Homily 7 on Romans).
Now, because all of this seems a great deal more theoretical than the negative imputation of our sins onto Christ, Catholics and Orthodox will accuse us Protestants of coming up with an innovation. I must respectfully disagree.
For one, Augustine interpreted 2 Cor 5:21 as teaching the positive imputation of Christ’s righteousness:
He does not say, as some incorrect copies read, He who knew no sin did sin for us, as if Christ had Himself sinned for our sakes; but he says, Him who knew no sin, that is, Christ, God, to whom we are to be reconciled, has made to be sin for us, that is, has made Him a sacrifice for our sins, by which we might be reconciled to God. He, then, being made sin, just as we are made righteousness (our righteousness being not our own, but God’s, not in ourselves, but in Him); He being made sin, not His own, but ours, not in Himself, but in us, showed, by the likeness of sinful flesh in which He was crucified, that though sin was not in Him, yet that in a certain sense He died to sin, by dying in the flesh which was the likeness of sin; and that although He Himself had never lived the old life of sin, yet by His resurrection He typified our new life springing up out of the old death in sin (Chapter 41, Handbook on Hope, Faith, and Love).
Many Protestant interpreters like to say that Jesus Christ was fully obedient to the letter of the Jewish Law, henceforth fulfilling the Law and its righteous requirements on our behalf. Not all ECFs affirmed this idea, but Athanasius did and he writes specifically that it is this righteousness that is credited to the Church:
It is necessary therefore it is necessary to believe the Holy Scriptures to confess him who is the first fruit of us to celebrate the philanthropy of him who assumed our nature to be struck with wonder at the great dispensation to fear not the curse which is from the Law for Christ hath redeemed us from the curse of the Law Hence the full accomplishment of the Law which was made through the first fruit must be imputed to the whole mass (Athan Synops Sacr Script lib vii in Epist ad Rom Oper vol ii p 125, see link here).
Christ redeemed us from the curse of the Law being made a curse for us Properly He was not under the curse because in all things He perfectly fulfilled the Law And therefore in the matter of debt our debt has been paid off by his curse so that He should set free from all obligation those who pass over to faith (Comment in Epist ad Galat iii, see link here).
Chrysostom also concurs, stating in his comments on Rom 8:4–
For the righteousness of the Law, that one should not become liable to its curse, Christ has accomplished for you.
Now there is more on the topic, but I think I have shown enough from both the Scriptures to justify Protestant doctrine and tradition to show that our doctrine is not an innovation. In fact, I would say that the burden of proof is on those that would teach that righteousness is infused into a believer and not a completed event:
An eternal rest remains to those who in the present life have wrestled legitimately which rest is given not according to the debt of works in way of just retribution but is bestowed to the grace of an abundantly bountiful God to who have hoped in Him (Basil, Homily on Psalm 104, see link here).
An eternal rest remains. It is a completed state, it is not a state that continues and grows over time. To God, the author and perfecter of our faith, be the glory forever. Amen.