This is the fifth post in a unit on salvation in my ongoing series, theology in bullet points. The first section had to do with God and Creation, and I have also finished units on Christology and Atonement.
God justifies us in response to our repentance and faith.
1. You may have heard the saying, "When I am justified, it is just-as-if-I'd never sinned." This childhood saying relates to the traditional sense that justification is about God declaring us legally right with him after he has forgiven our sins. In this way of defining the words, God's forgiveness precedes God's verdict that we are "not guilty" of all charges in his divine court.  Then after we are forgiven, God declares us to be in right standing before him. Justification is the act of God considering us in right standing before him. He declares us righteous, innocent, "not guilty" in the divine court.
In some respects, then, justification looks to our past, since "all have sinned" (Rom. 3:23). In our "natural state," as Wesley put it, we stand condemned before God, for "the wages of sin is death" (Rom. 6:23).  But despite our sins, God declares us righteous in his eyes. He gives us a clean slate legally.
Martin Luther emphasized that this righteous state was a legal fiction. That is to say, God's verdict is not based on what we really are. Like adoption, where someone who is not literally the child of another by blood is declared a child by law, so a person who is justified by God is not truly innocent but is declared so by God. However, this righteousness is as real as actually righteousness, even though it is "imputed," because God is the one who decides. God is the judge.
2. The normal process of coming to this righteous status before God begins with his prevenient grace. God reaches out to us. In our moral powerlessness, he gives us just enough power to respond to his call. If we continue to respond, he will give us the power to repent of our past sins and exercise faith in him.
Repentance is a regret for past sins and a turn away from them. It is not a regret of future punishment. It is a true desire that we had not done wrong and a sincere desire to change our actions in the future. In Acts 2:38, when the the crowds of Jerusalem realize that they have put their Messiah to death, Peter tells them to "Repent, and be baptized every one of you in the name of Jesus Christ so that your sins may be forgiven; and you will receive the gift of the Holy Spirit."
So also John the Baptist, in preparation for the Christ, preached a "baptism of repentance for the forgiveness of sins" (Mark 1:4). To the Gentiles, Paul in Acts 17:30 tells them that while God in the past has overlooked the ignorance of the nations, he was now commanding people everywhere to repent. Baptism, from this perspective symbolizes and sacramentally acts out the washing away of past sins.
If repentance is a negative action toward the past, faith is a positive action toward God in the present which continues into the future. Faith is more than mere belief or mental assent. Faith is a trust and conviction. It is a commitment that looks to the future. "if you confess with your lips that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved" (Rom. 10:9).
Paul here is talking here about a righteousness that comes by faith. Our English hinders us from seeing the full nuances of this passage. In Greek, the noun faith (pisteuo) and the verb believe (pisteuo) are clearly related. To believe can thus mean "to have faith," and faith can mean "belief." Here it is important to realize that words have more than one meaning and context determines which one is used in which individual instance.
In Romans 10:9, Paul is saying that, "if you have faith in your heart" in relation to what God has accomplished through the resurrection of Jesus, you will be saved. This act of faith is more than simply believing with your head that it happened. After all, it involves a confession that Jesus is Lord, that he is Master, that he is the king. "Everyone who calls on the name of the Lord shall be saved" (Rom. 10:13), but this is a call that gives him allegiance, not a mere cry for help.
Similarly, the verb "to justify" (dikaioo) and the nouns "righteousness" (dikaiosyne) and "justification" (dikaiosis) are clearly related as well. To speak of the "righteousness that comes by faith" (Rom. 10:6) is thus to speak of justification by faith.
3. The basis of our justification is the atoning death of Jesus, "whom God put forward as a sacrifice of atonement by his blood" (Rom. 3:25). Empowered by the Holy Spirit, the mechanism of our justification is faith: "a person is justified by faith apart from works prescribed by the law" (Rom. 3:28). Then once God has declared us righteous before him on the basis of faith (cf. Rom. 4:3), we are at peace with God (Rom. 5:1). We are reconciled to him (e.g., 2 Cor. 5:19).
4. You will notice that most of the biblical references above come from Paul's writings in the New Testament, Romans in particular. Accordingly, it is significant to remember that the language and imagery we have been discussing is not the only language of salvation in Scripture. It is only one way of looking at salvation, and it was forged in Paul's debates with certain opponents in the earliest church.
Indeed, language of justification is not even the primary language of Paul's letters. It is chiefly confined to Romans and Galatians, where Paul was dealing with opposition to the way he viewed the salvation of non-Jews. "Justification by faith" thus was not the center of Paul's theology but one set of language he used with Jews who opposed the way he conducted his mission to Gentiles. Romans is not a systematic theology but a letter written in part to defend Paul's way of including Gentiles within the people of God without requiring them to keep the Jewish Law.
There are thus a number of nuances to Paul's language that we are prone to miss because we are no longer facing the situations he was facing. This fact does not undermine the truth of the theology of justification above. What it does is suggest that this language is only one way of expressing the process of our reconciliation to God.
For example, when Paul spoke of Gentiles not being justified by "works of Law" (Rom. 3:28), he clearly had the Jewish Law in view. And what works of the Jewish Law does he primarily have in view? Surely it is primarily matters that separated Jew from Gentile. In Galatians, circumcision is primarily in view. Romans speaks in more general terms, but the point is that Paul does not have mere "good works" in mind. That is not what he is talking about. He is talking about any sense that a Gentile has to keep the Jewish Law in order to obtain a right standing before God. 
It thus would go well beyond anything Paul had in mind if we were deny that faith involves an act of the human will. Yes, justification is a matter of God's grace (Rom. 4:16), but as we have seen in previous articles, grace in Paul's world was a gift disproportionate to anything the recipient might do. Grace did not imply, however, that the recipient did absolutely nothing to solicit or maintain the grace. The faith of Abraham by which God considered him righteous was an act on Abraham's part. It reflected an investment in God that went beyond mere assent.
5. Another debate about Paul's original meaning focuses on the phrase, "the faith of Jesus Christ" (Rom. 3:22; Gal. 2:16). Many Pauline scholars believe that this expression had to do with the faithfulness of Jesus in death rather than our exercise of faith in him.  This is not a denial that faith in Christ was part of Paul's equation, for these two verses also use the verb "believe" with Jesus as the object. However, it might shift the emphasis in justification even further away from our faith toward the action of Jesus and his faithfulness to death (cf. Phil. 2:8).
In our view, the bulk of Paul's references to faith in Romans 4 and Galatians 3 are surely to human faith. Nevertheless, it is quite possible that Paul's focal statements in Romans 3:22 and Galatians 2:16 did refer to the faithfulness of Jesus as the basis of our justification. Paul would be affirming again that it is the atoning death of Jesus that is the ground of our right standing before God.
Nevertheless, this discussion does free us up to see that Paul primarily saw Gentiles and Jews as putting their faith in God the Father (e.g., 1 Thess. 1:8). We also put our faith in Jesus' death. But for Paul, almost all the mentions of human faith have God as their object (e.g., Rom. 4:3, 24).
6. A final nuance to mention about Paul's language is that the phrase, "the righteousness of God," in Romans 1:17 almost certainly referred primarily to God's righteousness rather than human righteousness or justification. Again, this nuance does not contradict the theology above but it reminds us that Paul's argument is placed against a long backdrop in history that goes back to Psalms and Isaiah. If you look at Psalm 143:1, for example, God's righteousness and his faithfulness are put in parallel to each other. In Isaiah 45:8, God's righteousness and his salvation are parallel.
In short, while Paul does speak of human justification in Romans, the idea of "the righteousness of God" had a history that suggests Paul's audience would have heard it in relation to God, in the first place, rather than something relating to humans.
God justifies us, he declares us in right standing before him, on the basis of the atoning death of Jesus Christ. He does this in response to our faith in him and in the death of Christ, which presupposes our repentance for past sins.
Next week S6. God fills us with his Holy Spirit as a seal of ownership.
 John Wesley's understanding of justification by faith and conversion can be explored in numerous sermons, including "Justification by Faith" and "The Spirit of Bondage and the Spirit of Adoption," With regard to justification, Wesley largely followed the lead of Martin Luther.
 See especially "The Spirit of Bondage and the Spirit of Adoption" above.
 For a discussion of "works of Law," see especially the essays in J. D. G. Dunn, A New Perspective on Paul (Grand Rapids: Eerdmans, 2007), esp. 8-10, 121-40.
 The most notable proponent of this view is Richard Hays, The Faith of Jesus Christ: The Narrative Substructure of Galatians 3:1-4:11, 2nd ed. (Grand Rapids: Eerdmans, 2002).