Faith is the means or instrument by which a person is saved. Christians are justified before God by faith (Rom. 3:26; 4:1-5; Gal. 2:16), and by faith they live their lives (2 Cor. 5:7) and sustain their hope (Heb. 10:35-12:3).

Faith cannot be defined in subjective terms, as a feeling or optimistic decision. Neither is it a passive orthodoxy. Faith is a response, directed toward an object and defined by what is believed. Christian faith is trust in the eternal God and His promises secured by Jesus Christ. It is called by the gospel as the gospel is made understandable through the gracious work of the Holy Spirit. Christian faith is a personal act, involving the mind, heart, and will, just as it is directed to a personal God, and not an idol or an idea.

It is usual to analyze faith as involving three steps: knowledge, agreement, and trust. First is knowledge, or acquaintance with the content of the gospel; second is agreement, or recognition that the gospel is true; and third is trust, the essential step of committing the self to God. These steps go together in the since that there can be Christian faith only when the gospel is known and its truth is accepted (Rom. 10:14).

Through faith we receive Christ, who satisfied the law on our behalf. In this way we are justified through faith alone, without doing the works of the law. But since faith unites us with Christ, it cannot be lifeless. Directed toward God and resting in Him, it is active, "working through love" (Gal. 5:6), seeking to do all the "good works, which God prepared beforehand" for us (Eph. 2:10). Justification is by faith alone, but justifying faith can never be alone.

When James says that faith without works is dead, he is describing a faith that knows the gospel and even agrees with it, but has fallen short of trust in God. Failure to grow, develop, and bear the fruits of righteousness shows that the free gift of God in Christ has never been received. The answer for those with such a faith is not to save themselves by establishing a righteousness of their own, as if they could create faith by their own efforts, but to call on the name of the Lord (Rom. 10:13). God alone can save those for whom it is otherwise impossible (Mark 10:27). Paul shows that good works cannot break this impossibility; James shows that the faith required is faith that rests in the living God.

Even when we have believed, the good works we do are never perfect. They are acceptable to God only because of the mercy of Christ (Rom. 7:13-20; Gal. 5:17). We express our love for God through doing what pleases Him, and He in His kindness promises to reward us for what we do (Phil. 3:12-14; 2 Tim. 4:7, 8). In this we are not making God our debtor, any more than when we first believed in Him. As Augustine noted, God in rewarding us is graciously crowning His own gracious gifts.

Sproul, R.C. Faith and Works. The Reformation Study Bible. Orlando: Ligonier Ministries. 2005. 1804