The doctrine of justification is crucial in the gospel of Jesus Christ and at the core of how we define Christianity. Justification answers the question of how a holy, righteous, and just God can declare sinners as righteous before His judgment seat. Justification is the legal declaration of God where He pardons all our guilt from sin giving it to Christ on the cross, and He transfers (imputes) Christ’s righteousness to us making us holy and blameless in His sight. Justification occurs in an instant as a result of union with Christ by faith alone. It is only by God’s grace and for His glory, and cannot be earned by any merit or work that we do. Justification is not the same as sanctification. These are two different doctrines in the Bible. Sanctification has to do with the process of being made holy over time as a believer. Sanctification comes after justification in the order of salvation. Justification is a once-for-all declaration of being made righteous by the work of Christ. Sanctification involves believers being made righteous and holy through God’s Spirit over their lifetime. Justification cannot be lost and does not have varying degrees.

While justification by faith is fully explained in the New Testament, the idea was also found in the Old. Job asked, “how then can a man be just with God?” (Job 25:4). When Abraham had faith in Yahweh it was “reckoned to him as righteousness” (Gen 15:6). To reckon here means to “count” or “impute” something from one person to another (see Rom 5:16–21). The word righteousness has to do with the conformity to the moral nature and will of God. David said, “How blessed is he whose transgression is forgiven, whose sin is covered! How blessed is the man to whom the LORD does not impute iniquity, and in whose spirit there is no deceit!” (Ps 32:1–2). Here we see that when a person finds forgiveness in God sin guilt is not counted against them. This type of forgiveness occurs when a person confesses and repents of their sin (Ps 32:5). Paul quotes from Psalm 32 when speaking of justification in Romans 4.

The New Testament contains an abundance of passages teaching justification. In Luke 18:9–14, Jesus tells the parable of the Pharisee and the tax collector. When the tax collector repents before God at the temple and asks for mercy, Jesus says, “I tell you, this man went down to his house justified rather than the other” (v. 14). Paul writes considerably about justification in his letter to the Romans. He makes clear in the first three chapters that “by the works of the Law no flesh will be justified in His sight” (Rom 3:20; Gal 3:11). But through faith alone a person can be reckoned as righteous (Rom 1:17; 3:28, 30; 4:5–8; 5:1; 10:6; Gal 2:16; 3:11, 24; Phil 3:9, Heb 11:7). God is the one who justifies (Rom 8:33–24) and justification is a gift of His grace (3:24). God is both “just and the justifier of the one who has faith in Jesus” (3:26). The basis of justification is the work of Christ alone (Rom 3:24–26; 5:9; 18–19; 2 Cor 5:21).

Often we see Paul talk about the doctrine of union with Christ and justification together. Through faith we are instantly united to Christ, which is why He takes our sin and guilt and we get His righteousness. Rom 3:24 says, “being justified as a gift by His grace through the redemption which is in Christ Jesus.” Working backwards through the verse, those who believe (v. 22) are in union with Christ and through being “in Christ” they have justification by grace through redemption. Again in Rom 8:1, Paul makes a connection between justification and union with Christ when he writes, “Therefore there is now no condemnation for those who are in Christ Jesus.” The “now” here means there is a present relation to God that a believer enjoys through Christ. The use of “in Christ” here points back to Rom 6:1–11 where Paul had established that the believer has been united with Christ in His death and resurrection. Therefore, the believer is no longer condemned but now justified as a benefit of their union with Christ which occurs through faith.

We now turn to 2 Cor 5:21, likely the only passage in the Bible which clearly states a connection between justification, imputed righteousness, and union with Christ. The verse reads, “He made Him who knew no sin to be sin on our behalf, so that we might become the righteousness of God in Him.” Since believers are declared righteous (justified) through the righteousness of Christ imputed to them, and His righteousness comes from being in union with Him, justification flows from being united to Christ by faith. This is why the theologian Charles Hodge could make his famous comment, “It is by virtue of our union with Christ, and only as we are in him by faith, that we are righteous before God.”

In Gal 2:17 we find a relationship of justification and union with Christ when Paul writes, “while seeking to be justified in Christ, we ourselves have also been found sinners, is Christ then a minister of sin? May it never be!” The logic of Gal 2:16–17 leads to the following order: faith in Christ brings about union with Him which leads to justification. Regardless of how we order faith and union, it is clear here that justification proceeds from union with Christ. Phil 3:8–9 is also another key passage, “…so that I may gain Christ, and may be found in Him, not having a righteousness of my own derived from the Law, but that which is through faith in Christ, the righteousness which comes from God on the basis of faith.” Here, Paul looks forward to being found in union with Christ so that he may participate in the resurrection (v. 11). The following clause “not having a righteousness…” shows in what way Paul will be found in union with Christ: not through his own righteousness but by that of Christ. Because of his union with Christ, Paul shares in Christ’s righteousness and his justification rests on this. Justification results in forgiveness of sins (Acts 13:38), the bestowal of divine favor (Rom 5:1), and peace with God (Rom 5:1; 2 Cor 5:19).

Justification is an astonishing doctrine when we consider how God can justify the godless sinners that we once were. Yet, His word has revealed that He does this through faith, which brings us to Christ. Through this union with Christ He takes on our sins and He gives us His righteousness. By this God declares us as righteous, He justifies us, in His sight. We must pray that true churches in the world continue to preach and teach the biblical doctrine of justification.