Imputation refers to the legal act of crediting or charging something to a person's account — not because it originated in them, but because of a representative relationship. Scripture presents three essential imputations that form the backbone of biblical soteriology:
1. Adam's sin imputed to all humanity. When Adam sinned, he acted as the federal head of the human race. His guilt was credited to his posterity — not merely that we inherited a sinful nature, but that his transgression was legally reckoned against us. Paul's argument in Romans 5:12–19 is explicit: "By one man's disobedience the many were made sinners." Death spread to all because all were reckoned guilty in Adam.
2. Our sins imputed to Christ. On the cross, the guilt and debt of the elect was credited to Christ's account. He did not become a sinner in nature, but He bore our legal liability. "He made him to be sin who knew no sin" (2 Cor. 5:21). Isaiah 53:6: "The LORD has laid on him the iniquity of us all." This is penal substitution resting on the mechanism of imputation — Christ paid a debt He did not owe because our debt was charged to His account.
3. Christ's righteousness imputed to believers. This is the blessed exchange at the heart of justification. Through faith, Christ's perfect, active obedience — His entire law-keeping life — is credited to the believer's account. We are not merely declared "not guilty" (as if sin were erased). We are declared positively righteous — as if we had lived the life Christ lived. Abraham "believed God, and it was credited to him as righteousness" (Romans 4:3). The righteousness is not his; it is Christ's, reckoned to him.
IMPUTA'TION, n. The act of imputing or charging; attribution. In theology, the imputation of sin is the charging of sin or guilt to one's account by divine reckoning; the imputation of righteousness is the crediting of righteousness to the believer, not inherent in himself, but belonging to Christ and reckoned to the believer through faith. The imputation of Adam's sin to his posterity, and the imputation of Christ's righteousness to believers, are doctrines of high importance in the Christian system.
Rome and the Federal Vision movement have attacked the doctrine of imputed righteousness, arguing instead for an infused righteousness — righteousness that is worked into the believer through the sacraments and cooperative grace, making justification a process rather than a verdict. This collapses the distinction between justification (what God declares) and sanctification (what God produces). If righteousness is infused, then the ground of my justification is partly my own improved moral character — and assurance becomes impossible, because I can never know if enough righteousness has been infused. The Reformers died defending the alien righteousness of Christ: it comes from outside of us, not from within. Luther's great cry was iustitia aliena — a righteousness not our own. The believer stands before God not in his own virtue but in the total, finished, credited righteousness of Christ. That is the only ground of absolute assurance.
Romans 4:3–8 — "Abraham believed God, and it was counted to him as righteousness… to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness."
Romans 5:12–19 — "By one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous." — Double imputation: Adam's sin in, Christ's righteousness out.
2 Corinthians 5:21 — "For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God."
Philemon 1:18 — "If he has wronged you at all, or owes you anything, charge that to my account." — Paul's personal illustration of imputation.
G3049 — λογίζομαι (logizomai) — to reckon, count, credit; the accounting word Paul uses 19 times in Romans 4 alone; it is a term drawn from commerce and law.
H2803 — חָשַׁב (chashab) — to reckon, account, impute; the OT equivalent used in Genesis 15:6 ("it was counted to him as righteousness") and quoted by Paul in Romans 4:3.
• "Imputation is the mechanics behind the miracle of justification. The verdict 'not guilty' is possible because the debt was paid; the verdict 'righteous' is possible because the righteousness was transferred."
• "God does not justify believers by making them righteous (infusion); He justifies them by crediting them with a righteousness they did not earn (imputation). The difference is the difference between Rome and Geneva."
• "The double imputation is breathtaking: my sin goes to Christ's account at Calvary; Christ's righteousness comes to my account at conversion. I am simultaneously the most bankrupt and the most wealthy man in the room."