Faith is belief in Jesus Christ as He has been prophesied about in the OT and testified about in the NT. Faith is a gift received by grace and not by works (Eph 2:8-9). On the other hand, true biblical faith produces fruit according to James 2:14-26. To put these to ideas together, God given faith will produce spiritual fruit in and through the life of the believer. A person who has been given the gift of faith can be certain of his/her salvation because God’s gifts and call are irrevocable.
In addition to this short answer, I think it may help if I include a portion from my thesis paper. One of my major interests at seminary was the relationship of faith and works.
The Nature of Faith
Active
Much of the debate over the differences between Paul and James could be resolved by their understanding of faith. In Romans 10:8, Paul says that the proclaimed word is in his audience’s heart even though the audience is filled with believers and non-believers. John 1:1 equates God with his Word. From this alone, one could say that Jesus was in the heart and mouth of those present when Paul spoke since Jesus and God are one. To obtain the word that is in their hearts, Paul declared that they must confess “Jesus is Lord” and believe in their hearts that God raised Him from the dead (cf. Rom 10:9). Paul’s plan of salvation in Romans 10:9 is composed of two primary parts: confession with the mouth that “Jesus is Lord” and belief (pi,stij) in the resurrection of Christ. But are mere words and pi,stijenough? If one affirms sola fide, as this author does, then why does the Christian even have to make a confession if faith is all that is required? Has Paul added works to the requirements of salvation by arguing for the need of a confession? Is Paul’s emphasis on a confession any different from James’ emphasis on charitable deeds?
Paul’s conclusion that a person is justified by faith apart from works is the basis of the sola fide doctrine. Clearly, Paul does not wish to add the confession “Jesus is Lord” or anything else to the requirement of sola fide (cf. Rom 10:9). Like Paul, James does not wish to add charitable works, works of the law, or anything else to the doctrine of sola fide either. He certainly does not wish to add fruitless words to the requirement of salvation (cf. Jas 2:15–17).
James argues in 2:17 that faith must be accompanied by deeds. At first glance, this seems to contradict the doctrine of sola fide. However, the perceived contradiction can be eliminated depending on the nature of faith. Is faith active, inactive, or somewhere in between? If real faith is faith that leads to demonstrable, charitable acts of love like those of Abraham and Rahab (cf. Jas 2:21–25), then saving faith must be an active faith.
James seems to acknowledge that true faith is present before works and independent of works in v. 18 where he demonstrates his faith by his action. James could not possibly demonstrate his faith by his action unless his faith was present before his action. His faith precedes the action and stands independent of the action. Though faith is independent of action because salvation is based on the action of Christ alone, it is displayed outwardly in the life of the believer.
To conflict with the sola fide doctrine of Paul, James would have to argue that a person was required to have works in order to be saved. James sees works as an expression of salvation rather than a means of salvation. Likewise, Paul also acknowledges works as an expression of true Christianity (cf. Gal 5:6; Rom 2:6; 14:12).
Paul in Galatians 5:6 declares that following Old Testament rituals is not what matters; what matters is faith that works through love. But the question must be asked: At what point in the justification process must love occur? Paul loved the churches and the Lord enough to endure much suffering in his day, yet before his Damascus experience he had set out to uproot the Church. Paul’s love for the Lord and for his people followed his salvation experience on the Damascus road. Love expressed through acts of charity, therefore, does not precede justification; rather, “justification is their precondition and the root from which they grow.”[1]
Heartfelt
James states in 2:19 that demons have faith. Surely the faith of the demons is not the same as the active faith that James claims to have in 2:18. Scripture clearly shows that demons are aware of Jesus’ authority (cf. Matt 8:31; Luke 8:27). The demons were aware that their destination was the lake of fire according to Matthew 8:29. If the faith of the demons did not have saving power, what was their faith lacking? In Matthew 7:22–23, Jesus rebukes those who recognize him and do many great things in his name. Recognizing Jesus (intellectual faith) and doing good works (right action) is simply not enough, what is needed is a pure heart with an obedient spirit.[2] True faith springs forth from a pure heart leading to an active expression in the life of the Christian.
Justified
Paul appeals to Genesis 15:6 to argue that the “initial step of faith” was the basis for Abraham’s being declared justified (cf. Rom 4:3, 9–10). James examines Abraham’s actions in 2:21–23 that occurred many years after his initial faith experience. The compatibility of Romans 3:28 and James 2:24 depends on their definition of justification. Pauline theology typically portrays justification as meaning the presence of a right relationship between God and the person through the person’s faith in Christ’s atonement assuring the person’s acceptance by God into his kingdom. Paul, however, strays from this definition of justification in Romans 3:4 when he uses the term to connote vindication.
[1]Bornkamm, Paul, Paulus, 153.
[2]cf. Deut. 4:29; 1Chr. 28:9; 2 Chr. 7:14, 15:12; Psa. 24:4–6, 63:1, 119:2, 119:10; Isa. 51:1; Jer. 29:13; 2 Tim 2:22; Heb. 11:6.