Genesis 15: Forensic Imputation and Justification

Genesis 15 is the primary Old Testament example for the doctrine of justification by faith. In Genesis 15 Abraham “believed God and it was counted to him for righteousness” ([13:07]). Abraham remained a sinner in himself, yet God legally “counted” or “reckoned” him as righteous because of his faith in God’s promise. That divine counting is the central idea of imputation: God credits righteousness to a person’s account on the basis of faith rather than on the basis of the person’s own moral perfection or works ([14:04]).

Imputation defines justification as a forensic, declarative act. To impute means to transfer legally to somebody’s account; God imputes Christ’s righteousness to believers in the same way He credited righteousness to Abraham ([14:04]). This is not an internal infusion of righteousness that first makes a person inherently righteous before God declares them just. Instead, justification is a legal declaration in which the righteousness of Christ—righteousness that is “alien” to the sinner (extra nos)—is credited to the believer’s account ([11:33]). This contrasts with views that treat justification primarily as an internal transformation that must precede God’s declaration ([08:48]).

Romans 3:21–26 articulates the same basic truth: no one is justified by the deeds of the law; the righteousness of God is revealed apart from the law and is received through faith in Jesus Christ by all who believe ([04:51]). The broader context of Romans 1–3 underscores universal human sinfulness—“all have sinned and fall short of the glory of God”—so that no one can be justified by their own efforts or law-keeping alone ([07:13]). The decisive answer to the question of how a guilty person can stand before a holy God is that God credits the righteousness of Christ to the one who believes, just as He credited righteousness to Abraham ([13:07]).

The biblical awareness of sin highlights the necessity of imputation. If the Lord were to mark every iniquity, no one could stand; conscience and Scripture alike show that human guilt makes self-justification impossible, thereby creating the need for a righteousness that can be received by faith alone ([07:13]).

The Reformers summarized the believer’s condition with the formula simul justus et peccator: simultaneously righteous and sinner. Believers remain sinners in themselves, yet they are declared righteous because Christ’s righteousness has been legally credited to them by faith ([16:04], [17:05]). This captures a crucial tension: justification concerns the status God assigns, not an immediate eradication of sin within the justified person.

Key doctrinal points:
- Justification is a forensic declaration by God, not merely an internal moral transformation. God declares sinners righteous on the basis of faith in Christ, crediting Christ’s righteousness to them ([14:04], [04:51]).
- Imputation means the righteousness that justifies is legally transferred to the believer’s account; it remains “extrinsic” to the sinner and is received by faith (extra nos) ([11:33]).
- Genesis 15 provides the foundational Old Testament example for this doctrine: Abraham’s faith, not his works, was the ground on which righteousness was counted to him ([13:07]).
- The universal diagnosis of sin in Romans 1–3 and the Psalmist’s recognition that none could stand if iniquity were strictly marked point to the necessity of a righteousness supplied and imputed by God ([07:13]).
- The doctrine undergirds the Reformation’s emphasis that justification by faith alone is central to the gospel; it has been called the article upon which the church stands or falls ([20:18]).

Justification, therefore, is the legal act of God by which He declares sinners righteous on the basis of Christ’s perfect righteousness credited to them through faith. This declaration is a gift of God’s grace, received by faith, and not a reward for human achievement or inherent moral fitness.

This article was written by an AI tool for churches, based on a sermon from Ligonier Ministries, one of 1525 churches in Sanford, FL