Imputed righteousness is a theological concept directly related to the doctrine of Justification. It is particularly prevalent in the Reformed tradition.
“Justification is that step in salvation in which God declares the believer righteous. Protestant theology has emphasized that this includes the imputation of Christ’s righteousness (crediting it to the believer’s “account”), whereas Roman Catholic theology emphasizes that God justifies in accord with an infused righteousnessmerited by Christ and maintained by the believer’s good works,” (Elwell Evangelical Dictionary). Imputed righteousness therefore means that upon repentance and belief in Christ, individuals are forensically declared righteous. This righteousness is not the believer’s own, rather it is Christ’s own righteousness ‘imputed’ to the believer.
A primary line of argumentation for this doctrine maintains that perfect righteousness or holiness is necessary to be with God. All mankind “fall short of the glory of God” (Rom 3:23) because all their ‘righteousness’ is like filthy rags (Is 64:6) before the throne of God, and so all are “dead in their trespasses and sins” (Eph 2:1), and as a result “will not come into [God’s] light for fear that their evil deeds will be revealed” (John 3:20). All mankind is in this predicament because all are the offspring of Adam and Eve (Rom 5) who originally sinned against God. As a result of Adam’s fall, the world was cursed and sin entered the world. But upon confession of one’s own sin and faith in Christ’s death and resurrection, the sinner is justified and counted as having the righteousness of Christ.
Imputed righteousness is one of the classic doctrines of Protestantism and traces back through the Reformers – chiefly John Calvin and Martin Luther. These men stood against the Roman Catholic doctrine of infused righteousness where the righteousness of the saints and of Christ is gradually infused to the believer through the sacraments. For the Catholic, infused righteousness either gradually dissipates as the believer takes part in worldly sins or is enhanced by good works. If the believer dies without having the fullness of righteousness, coming in part from the last rites, he or she will temporarily spend time in purgatory until the sinful status is purged from his or her record.