As we endeavor to understand the Doctrine of Justification, we can begin with a theological definition of the term. Then we will unpack the definition and explain it through the verses of scripture as the Apostle Paul does so in his books of Romans and Galatians. Before we tackle the theological definition, a short simple definition is a good way to warm-up to the longer definition. One way that has been used to remember the term is to think of justification as meaning; “just as if I had not sinned.” That is, justification is the act of God by which He declares that a sinner is forgiven and is no longer under the penalty for his sins. He is imputed (credited) with the perfect righteousness of Christ because of his faith in Christ. He is not actually righteous but is covered with the righteousness of Christ which frees him from the guilt of sin. Another point to remember is that justification is required because mankind has been condemned by the sin and disobedience of Adam, and has been separated from fellowship with God. The sacrifice of Christ on the cross brings justification to the believer by his faith and brings him back into fellowship with God.
Definition of Justification: Justification is the judicial act of God in which He declares that the believer is righteous on the basis of the righteousness of Christ imputed to him. The divine verdict of ‘justified’ does not mean that the sinner is himself inwardly just. Justification means that God asserts that no charges will be brought against the believer and that His wrath no longer rests on him. The believer is forgiven, acquitted, adopted, and welcomed into God’s family.
“Justification is the judicial act of God.”- Justification in the Protestant view is a forensic term. The word forensic indicates something used by the courts, or legal system. The first sentence of the definition is indicating that the justification of a person is through a judicial act of God.
“in which He declares that the believer is righteous on the basis of the righteousness of Christ imputed to him.”- The declaration of righteousness is based on the righteousness of Christ and not on the righteousness of the believer. The believer is credited with the righteousness of Christ because of his faith in Christ and His work of atonement. The transfer of righteousness is part of a two-part exchange between the believer and Christ. This is called the double imputation. In the first part of the exchange the sins of the believer are imputed or credited to Christ, who has already paid the penalty for the sins through His death on the cross. The second part of the exchange occurs when the righteousness of Christ is credited to the believer. Christ’s righteousness is the righteousness He earned during His earthly ministry when He lived a perfectly sinless life.
“Justification means that God asserts that no charges will be brought against the believer, (Rom. 8:33), and that His wrath no longer rests on him.”- In Romans 8:33, the Apostle Paul affirms that those who God justifies will no longer face the charges for the penalty of sin; “Who will bring a charge against God’s elect? God is the one who justifies.” The rebellious unbeliever will receive God’s wrath at the time of judgment, while the believer has peace with God because God’s wrath against him has been satisfied by the sacrifice of Christ.
“The believer is forgiven, acquitted, adopted, and welcomed into God’s family, (Rom. 5:1-2, Acts 13:38-39. Gal. 4:5).”- Because justification is a legal term, we can think of the end result in the same way. The believer is forgiven and acquitted of all charges. He is then released from the court room and freed from custody. Before leaving he is informed that he has been adopted into the family of God. This is the doctrine of Adoption, which is wonderfully illustrated by the Puritan, Richard Sibbes;
“We are indwelt with the Holy Spirit who comes to reside with us in our homes. The Spirit then introduces us to the love of the Father and the Son, Who also make their dwelling place with us.”
The forgiveness of the believer must be considered in light of the mercy of God, Who provides the opportunity for justification and salvation entirely by His good grace. It is a gift given to His elect and it is not based on the works or the merit of the believer. The believer only accepts this gift by his faith.
UNION WITH CHRIST
God’s declaration of justification cannot be considered apart from the person’s union with Christ. The believer’s acceptance of Christ as his Lord and Savior through faith unites him forever with Christ. This union begins with the double-imputation and continues into his justification, and into his glorification after death. Union with Christ is essential to salvation and to the entire Christian life. The concept of a person’s union with Christ is explained by Jesus in the parable of the True Vine in John, chapter 15. In summary, this teaching is that the relationship between Jesus and His followers (believers) is like that of a vine and its branches. The branches are connected to the vine and are dependent on it for life. If the branches should become separated from the vine they would wither and die. The Christian is also dependent for his spiritual life on Christ and is nourished by this union. Justification is not possible without union with Christ.
SCRIPTURE VERSES SUPPORTING THE DOCTRINE OF JUSTIFICATION
Christians are justified by their faith in Christ
“7Therefore, be sure that it is those who are of faith who are sons of Abraham. 6Even so Abraham believed God, and it was reckoned to him as righteousness. 8The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, “All the nations will be blessed in you.” (Gal 3:6-8)
This verse shows that Abraham was justified by his faith and was credited with righteousness by faith. Here, Paul is referring to Gen. 15:6 where the justification of Abraham was a foreshadowing of God justifying the Gentiles in the same way in the future. God’s plans of justification by faith have their roots in the Old Testament and were eventually realized in the ministry of Christ on earth. Paul found it necessary to defend this doctrine as it contradicted the view held by Judaism. Their belief is that justification is received through obedience to the law of Moses. This teaching of Christ and His apostles was heresy in their eyes and needed to be abolished. Paul showed them that their founding father, Abraham, was himself justified by his faith even before the law existed.
Believers receive righteousness from God through faith
21“But now apart from the Law the righteousness of God has been manifested, being witnessed by the Law and the Prophets, 22even the righteousness of God through faith in Jesus Christ for all those who believe; for there is no distinction; 23for all have sinned and fall short of the glory of God, 24being justified as a gift by His grace through the redemption which is in Christ Jesus; “(Rom. 3:21-24).
Justification brings the righteousness of God through faith to the believer, apart from the law. The righteousness of Christ is given to all those who believe in Him.
Righteousness is credited to the Believer
8“Blessed is the man whose sin the Lord will not take into account.”9Is this blessing then on the circumcised, or on the uncircumcised also? For we say, “Faith was credited to Abraham as righteousness.”10How then was it credited? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised; 11and he received the sign of circumcision, a seal of the righteousness of the faith which he had while uncircumcised, so that he might be the father of all who believe without being circumcised, that righteousness might be credited to them,” (Rom. 4:8-11).
Paul refers again to Abraham to explain the transfer of righteousness from God to the believer by faith. He uses the term credited which is synonymous with imputation to explain this transfer. Abraham received his righteousness in the same way that believers receive righteousness in their justification. In his commentary of the book of Romans, Grant R. Osborne explains the idea of crediting righteousness by faith. Below is an excerpt:
Faith Credited as Righteousness for Us as Well (4:23–24)
The key phrase from Genesis 15:6 is “credited to him,” since it is the idea behind the theology of justification by faith: God takes our faith in Christ and on that basis credits it to our account, enabling him to declare us righteous. Thereby Abraham’s faith and God’s justifying activity in him becomes the primary Old Testament model for the new covenant established by the atoning sacrifice of Christ.
Redemption thereby requires not the “works of the law” stemming from Moses but the “faith credited as righteousness” stemming from Abraham. There is no merit theology in Christianity. When we exercise the same faith Abraham did, then for us as well this faith is “counted as righteousness.” Paul adds here that this very faith “credited to him” on the part of Abraham was never intended “for him alone, but for us,” namely, “for our sake.”
In verse 24 Paul describes the Christian in two ways in light of justification by faith. First, believers are those “to whom God will credit righteousness,” the very point Paul has developed throughout 3:21–4:25. Some take this as a reference to the last judgment more than to conversion on the grounds of the Greek “about to credit” (niv “will credit”), which might convey the future act of God at the consummation of history when he provides the final “justifying” act for his people. However, the emphasis throughout 3:21–5:11 is on the present justification of sinners. Present conversion seems the better understanding, as there is no hint of future judgment in chapter 4 (it will come up in 5:9). It is possible that both aspects are intended here, but if so the primary stress by far is on the present aspect.
Second, we are those “who believe in him who raised Jesus our Lord from the dead.” Paul here is emphasizing on the phrase “believe in him who,” with God as the focus of our faith. Once again, God is the focus of this chapter, for it is he who makes faith possible and who justifies those who believe. This is slightly unusual, as Paul normally emphasizes faith in Jesus, but the parallel with Abraham’s faith in God is behind this thrust.
The stress here flows out of verse 17, where Paul emphasized Abraham’s faith in “the God who gives life to the dead.” There Paul was referring mainly to Abraham’s “dead” body given “life” through the promised son, Isaac. The promise to Abraham is a foretaste of the greater promise that is ours through Christ, with his resurrection the firstfruits for us (1 Cor 15:20, 23). Jesus the Messiah, who delivered us through his death, is also the elevated “Lord,” sovereign over us and giver of eternal life.
 Grant R. Osborne, Romans: Verse by Verse, Osborne New Testament Commentaries (Bellingham, WA: Lexham Press, 2017), 129–130.