Gospel Guidebook: Getting and Keeping It Right 
The Relationship between Faith and Works in Key Passages
Although I have dealt with the relationship between faith and works in my articles Positive Correlation between Faith and Works, Faith Does NOT Produce Works, Works are NOT Evidence of Saving Faith, and Faith is NOT Like a Fruit Tree, there is more to say on this topic. I believe James 2 gives us the principles for understanding the nature of faith, namely that (1) faith by itself is idle (literally "dead"), just like a body without a spirit is idle; (2) faith is empowered by works just like a body is enlivened by a spirit; (3) faith can work together with works and create beneficial synergy; and (4) faith is perfected by works similar to how fire is perfected by wind. In this article, I will look at Luke 7:36-50 and 1 John 3:14-15 and see how these principles apply. If we can understand these two passages of Scripture through these principles, not only will be able to validate the truthfulness of the principles themselves, but also be able to equip ourselves with a hermeneutical rule for understanding similar passages.
In Luke 7:36-50, Jesus was invited to a Pharisee's house. While He was there, a woman (who was known to be a notorious sinner) came and prostrated herself at His feet and wiped His feet with her tears. When the Pharisee doubted Jesus' legitimacy as a prophet, Jesus answered him with a parable, concluding that 47 "For this reason I say to you, her sins, which are many, have been forgiven, for she loved much; but he who is forgiven little, loves little." 48 And He said to her, "Your sins have been forgiven." 49 And those who were reclining at the table with Him began to say to themselves, "Who is this man who even forgives sins?" 50 And He said to the woman, "Your faith has saved you; go in peace."
If all we had was verse 47, we wouldn't be able to make any firm conclusions. However, in verse 50, Jesus tells us that it was her faith that saved her, so this dispels any theory that it was her works of gratitude that procured forgiveness of sins. In contrast, theologians who define faith to include a works-producing element (such as fiducia) might be tempted to see an inherent causal relationship between her knowledge of forgiveness and her works of gratitude. However, this cannot be logically deduced and it requires defining faith in an unnatural and unbiblical way. The description of faith in James 2 leaves no room for fiducia or any other works-producing element, since faith is likened to a body without a spirit, idle in itself and incapable of doing anything. Also, as noted elsewhere on this website, the word translated "faith" in English Bibles corresponds to a Greek noun that could more literally be interpreted as "belief," being a cognate of the verb "believe." In every realm of life, "belief" simply means "to accept something as true," being merely a state of the mind. As such, it makes more sense to interpret the relationship between her knowledge of forgiveness and her works of gratitude from the viewpoint of positive correlation. Certainly, faith can (but not necessarily) influence works, and influence implies some degree of causation, but because there are many confounding variables (such as motivation, circumstances, irrationality, etc.), it cannot be said that faith consistently causes certain types of behaviors (see the next paragraph for more on this point). Again, James 2 supports a positive correlation between faith and works, but (perhaps surprisingly) does not describe a causative relationship. James explains that faith can work with works and can be perfected by works, but always describes faith and works as separate concepts. From the viewpoint of James 2, the woman's recognition of forgiveness worked with acts of gratitude, and it is unquestionable that her works brought her closer to Jesus and perfected her faith. Like Abraham, her works displayed to other people that she was the "friend of Jesus." However, at no point did her works serve as assurance or evidence of forgiveness. She was totally infatuated with her Savior and her works only served to increase this infatuation and strengthen her faith, culminating in Jesus' own affirmation of her faith when He told her directly that her sins were forgiven.
What more can be said about this positive correlation between faith and works? I think it is important to note that there is not a one-to-one correspondence between faith and works. Faith is capable of existing without works, so even if works go to zero, this doesn't necessarily mean that faith is absent or non-existent. The whole point of justification by faith apart from works is that faith is literally alone, meaning that there is no necessary relationship between the two. As I have shown in the articles linked above, there are many examples in the New Testament where faith isn't accompanied by works and other examples where works are performed without faith. And even in Luke 7:36-50, there is a hint of this. The Pharisee who invited Jesus was not hospitable, and displayed a hard heart toward the woman. However, in the parable that Jesus told him in verses 41-42, Jesus seemed to imply that he also had been forgiven his sins. Jesus then blamed his lack of gratitude on his lack of recognition of forgiveness (again indicating the same positive correlation between faith and works). As noted above, faith can influence works, but as pointed out by the interlocutor in James 2:18-19, faith is not associated with consistent behavior. In other words, while we might expect to see the same faith and the same works together (correlated and causative), we often see the exact opposite. The interlocutor explains that men and demons can believe the same thing about God, but not have the same response. A man who believes in one God "does well," while a demon with the same belief "trembles." The interlocutor shows that there is no inherent connection between faith and works. James never rebuts his interlocutor. The interlocutor's words are true and reflect reality, but for James, they are really a moot point because James never intended to convey such a connection between faith and works in verses 14-17 (although he obviously understood that some people would misunderstand him, and thus he needed to insert the interlocutor's words). Rather, James calls his interlocutor a foolish person because the interlocutor fails to see benefits of adding works to faith (see also 2 Peter 1:5ff.). Therefore, James spends the rest of the chapter in verses 20-26 giving examples of the good things that can happen when faith and works get together. Getting back to the case of the Pharisee and the woman, based on Jesus' parable, I think we can presume (with some confidence) that they both believed in Jesus and both had forgiveness of sins, but their faith did not elicit the same response. Faith does not exist in a vacuum, and as mentioned above, even when it influences works, there are other confounding variables that can overpower faith and result in very different types of behavior.
People may be wondering how James can say that faith by itself is idle (literally "dead"), yet there still can exist a causal relationship between faith and works due to the potential influence of faith. This may seem contradictory at first, but it is important to emphasize that there is no inherent causal relationship between faith and works, and any causal relationship that can exist due to influence is not by necessity. Also, James said that there are benefits that occur when faith works with works, so the benefits can act as a causative incentive, creating a correlative rather than a causative relationship between faith and works. It is often hard to distinguish between the relationship. For example, when Paul said, "I believed, therefore I spoke" (2 Corinthians 4:13), this seems to indicate that faith caused his works, but we can't say that with certainty because it might be that his faith created the potential for benefits (such as people getting saved and intimacy in his relationship with God), and that these benefits created an incentive that became the dominant cause of the works. In this case, there would be a correlative relationship between faith and works, not a causative relationship, yet we would still be able to say, "I believed, therefore I spoke." Without the incentive, faith and works would have never gotten together. But getting back to the main question, how can faith be described as idle and still be able to exert an influencing force? I think this can be understood by way of analogy. Faith is like money. Money by itself can do nothing. But it can (but not necessarily) influence people's behavior. However, there is no inherent causal relationship between money and behavior. Also, there are other confounding variables, such as the circumstances of life, that can cause people with money to behave in ways that seem contrary to what we would expect of people with money. Moreover, when money is combined with labor, products, and services, there is potential for many benefits. And these potential benefits can act as an incentive and dominant cause behind the relationship between money and behavior. In such a case, we can say, "I had money, therefore I bought," and not be speaking of a causal relationship between money and works, but a correlative relationship.
Let's move on to 1 John 3:14-15. We know that we have passed out of death into life, because we love the brethren. He who does not love abides in death. Everyone who hates his brother is a murderer; and you know that no murderer has eternal life abiding in him.
First, I'll give what I think is the most natural interpretation, and in the next paragraph, I'll proceed to analyze the less natural "test of true conversion" approach to interpreting these verses. To start, we have to consider what John means by "we." Is he speaking generally about all Christians or is he speaking specifically about himself and other apostles? While the former seems more natural in the English, the word "we" is emphatic in the Greek, so it might be that John wants to contrast his own experience against the hatred displayed by the world (verse 13) in order to defend and promote the way of brotherly love. Either way, he obviously wants to encourage his letter's recipients to act accordingly. Next, what does he mean by "know"? The context indicates that he uses the word "know" to mean "experience." Christians experience resurrection life when they love other brothers. Of course, if Christians have eternal life, they can experience it in their everyday lives by loving fellow Christians. This is what John means by having eternal life abiding in them. When Christians don't love their brothers (and please note that "fake Christians" or "false converts" don't have a brother to hate), they are not living in a manner in which the eternal life they possess abides in them. This interpretation really has no bearing on our understanding of faith and works.
For the sake of argument, what can we say about these verses if we attempt to interpret the word "know" as a way of deducing whether or not one has passed from death to life (i.e., as a test of true conversion)? I'd say that this view is still consistent with the principles we've learned from James 2. As mentioned above, works of love can empower faith, and when faith is empowered, obviously assurance is also strengthened. This is that positive correlation between faith and works that I have been talking about. Just to repeat, it is not the works that give us assurance/evidence of passing from death to life, but the empowered faith that gives us greater assurance as we become more persuaded by sacrificial love of Christ. In this way, we come to "know" that we have life.
However, it is important to notice that John's statement is a positive one. He says nothing about the reverse situation, namely that a lack of love means that we can know that we have not passed from death to life. This shows the logical weakness in the "test of true conversion" approach. For sure, John says that such a person "abides" in death, but in John's writings (i.e., his Gospel and letters), the word "abide" always refers to experience, not to positional truth. More specifically, the experience of eternal life, and even the possession of eternal life, must not be confused with justification by faith, which is a benefit "in Christ" (according to the Apostle Paul's usage of the phrase) that is entirely forensic (being a legal term that is contrasted with condemnation). In fact, John himself, in similar manner to Paul, says that the only "condition" (for lack of a better word) for inceptively receiving eternal life is bare belief, i.e., the reception of the testimony of God as being true in 1 John 5:9-13. In John 1:12, he says that belief in Jesus gives a person the "authority" to be born again as a child of God. I have argued elsewhere (here and here) that justification precedes regeneration and that this "authority" may very well refer to justification. So, in light of this, the "test of true conversion" fails to be a true test because it is possible for a person to fail the test and still be justified by faith. However, as I mentioned above, the interpretation of these verses as a "test of true conversion" is weak to begin with, and I think they should be more naturally interpreted as I did initially. At any rate, the principles we learned in James 2 apply to 1 John 3:14-15, and in fact, to all other verses in 1 John.
In this article, we looked at two key passages and saw that the principles of James 2 can be applied to them quite easily. And this is exactly what I expected because Scripture is consistent with itself. Having looked at these passages, as well as the passages in the other articles linked above, I feel confident that James 2 gives us a good hermeneutical rule for understanding similar passages in 1 John.