When talking to others about how Roman Catholics are not Christians, i.e. regenerate children of God, I have often heard the following response:
You should be careful about what you’re saying. After all, no one is justified by believing in Sola Fide.
This popular sentiment owes its origin to the heretical theologian, N.T. Wright who says:
We are not justified by faith by believing in justification by faith. We are justified by faith by believing in the gospel itself—in other words, that Jesus is Lord and that God raised him from the dead.
While Wright is correct in saying that we are not justified by faith by believing in justification by faith, he is not saying anything that Christians don’t believe. Christians assert that one is justified by grace alone through faith alone in Christ alone; we don’t assert that one is justified by believing in the doctrine of how one is justified. Wright is simply trying to pull a fast one on his readers, and in the process insinuate that to emphasize the necessity of holding to the doctrine of justification by faith alone is to add to the Gospel.
So why then do we say that a person who rejects the doctrine of justification by faith alone is not saved? Well, sola fide (faith alone) is a shorthand way of expressing how one is put in right standing with God. It means that the sinner who trusts in Jesus’ perfectly complete atoning sacrifice and righteousness for them, and this alone, is forgiven of all of his sins (Rom 4:1-8), granted peace with God (Rom 5:1), and has the righteousness of Jesus Christ imputed to him (Rom 3:21-26; 2nd Cor 5:21). So if someone comes along and denies that justification is by faith alone, they are rejecting the idea that they are put in right standing solely by the perfectly complete atoning sacrifice and righteousness of Jesus Christ for them. They are adding to the Gospel, embracing in its place a false gospel.
Note the words “perfectly complete atoning work and righteousness of Jesus Christ.” What we are intending to communicate to unbelievers is that there is no other object of trust for the sinner but Christ’s atoning work and righteousness for them. If there is no other object of trust, then one can only trust in the one object of faith and receive whatever God has promised to the one who believes in that perfect object of trust. Because Christ’s work of atonement is perfect and complete, and because his righteousness is perfect and complete, there is no other object of faith put forth for us. Thus, to reject sola fide is to state one’s belief that Christ’s atoning work and righteousness are insufficient to save the sinner. And if one believes that Christ’s atoning work and righteousness are insufficient to save the sinner, then he is lost and under the wrath of God. This is all of Romanism’s priests and her pope.
According to the Scriptures
If someone responds by saying that we have added to the Gospel by saying that one must believe in the perfectly complete atoning sacrifice and righteousness of Jesus Christ for them (i.e. penal substitutionary atonement), we state that we are simply elaborating on what Paul says when he declares that “Christ died for our sins in according to the Scriptures.” Paul’s meaning is not simply that Christ fulfilled the Scriptures, but that his fulfillment of the Scriptures achieves the ends for which God purposed it and reveals in the Scriptures. The New Testament is, after all, organically related to the Old Testament. We are not Marcionites.
Christ’s death is to be understood in accordance with Scripture (i.e. according to its historical occurrence and theological significance). Likewise, Christ’s resurrection is be understood in accordance with the Scriptures (i.e. according to its historical occurrence and theological significance). This means that the hackneyed and abused lines thrown out by papists, New Perspective on Paulists, Federal Visionists, and N.T. Wright, exemplified in the quotes opening this article, must be put to death.
To believe the Gospel is to believe that by faith in Christ we have peace with God. And to believe that is to believe that one is justified by faith alone.
Soli Deo Gloria.
 “New Perspectives on Paul,” in Justification in Perspective, ed. Bruce L McCormack (Baker Academic, 2006), 261.
 1st Cor 15:3.