The following was written in partial fulfillment of the requirements of Dr. Steve McKinion's Christian Theology II class at Southeastern Baptist Theological Seminary.
Topic: What does it mean to be "justified"?
Any discussion of the work of God in Christ has to include the idea of justification: it is an important throughout the Bible, and is especially prominent in Paul’s writings on salvation (which comprise a substantial part of the New Testament and most of our systematically theological reflection on salvation arises). The word “justify” and its nominal forms are used to translate words from the dikaoō (δικαιόω) word group in Greek, which includes a number of related concepts, all circling in various ways around the notion of justice and right action and just and righteous character. Since “justification”—being justified—before God is a central idea in Scripture and an essential element of our salvation, we should be careful to understand what exactly this concept means.
Most basically, for a person to be justified is for him or her to be righteous, and correspondingly to have acted rightly—in the eyes of God. At a bare minimum, this of course requires both the performance of good works and the rejection of sin. However, justification means more than simply having checked off a series of boxes corresponding to specific good works while having avoided other boxes corresponding to bad or sinful actions. It means being regarded as having done righteously and justly by God, and God sees our hearts, so even doing what is right and shunning what is wrong may not be sufficient: we often have entirely the wrong motives in such actions. We seek the approval of men instead of to please God; we want the social or personal benefits that follow from doing nice things for others; we enjoy stoking the fires of our own pride. In any case, we do not even act rightly, still less do so for the glory of God. So the idea that we might be justified on our own merits is hopeless.
Second, we should note that ordinary notions of justification often tend to include many of the right (that is, Biblical) concepts of justification in them, but in shallower forms than Scripture supplies. In particular, the use of the term has shifted somewhat from when it was used to translate the word group from Greek into English. When we say, “he was justified,” we do not mean that someone did the right thing, but that whatever someone did, he had grounds for doing. We can of course turn this back to our needs by noting that we have grounds only for right-hearted obedience and none for sinning. Still, this is less than the biblical idea of justification—of being considered to have done rightly in every way.
For the “Christian” to be justified, we must be able to stand before God and he consider us righteous in every word and deed and thought and attitude of the heart. This happens in two ways (inseparable from each other): forensic justification and imputed righteousness through union with Christ. In “forensic justification,” God legally acquits us of guilt for committed sin and righteous deeds left undone. The list of offenses we committed was nailed to the cross (cf. Colossians 2:13–15). This can happen because we are united with Jesus the Son of God by the Spirit of God. As Paul notes in 2 Corinthians 5:21, the sinless Christ became sin that we might become the righteousness of God. All that is Christ’s is ours; we are one with him and so we have all his righteousness. (The word “righteousness” here derives from the same root as we translate “justification”—these ideas are inextricably linked.) Finally, God himself justifies us, calling us righteous, because Jesus Christ has both lived in perfect righteousness and paid the penalty for our sins, propitiating the wrath of God (cf. Romans 3).