Many people assume that by trying to live a good life, they have done all that is necessary to get to heaven. They rest their confidence on the good works they have performed to satisfy the demands of God's justice.
This is a futile hope. God's law requires perfection. Since we are not perfect, we lack the necessary goodness to enter heaven. Thus goodness can never be achieved by living a good life. We can only receive it by trusting in the righteousness of Christ. His merit is perfect and is made available to us through faith.
To believe that we are justified by our good works apart from faith is to embrace the heresy of legalism. To believe that we are justified by a kind of faith that produces no works is to embrace the heresy of antinomianism.
The relationship of faith and good works is one that may be distinguished but never separated. Though our good works add no merit to our faith before God, and though the sole condition of our justification is our faith in Christ, if good works do not follow from our profession of faith, it is a clear indication that we do not possess justifying faith. The Reformed formula is "We are justified by faith alone, but not by a faith that is alone." True justification always results in the process of sanctification. If there is justification, sanctification will inevitably follow. If sanctification does not follow, it is certain that justification was not really present. This does not mean that justification depends or rests upon sanctification. Justification depends on true faith, which in turn will inevitably lead to works of obedience.
When James declared that faith without works is dead, he asserted that such "faith" cannot justify anyone because it is not alive. Living faith produces good works, but these good works are not the basis for justification. Only the merit achieved by Jesus Christ can justify the sinner.
It is a grievous error, indeed a modern form of the antinomian heresy, to suggest that a person can be justified by embracing Jesus as Savior but not as Lord. True faith accepts Christ as both Savior and Lord. To rely on Christ alone for salvation is to acknowledge one's total dependence upon Him and to repent of one's sin. To repent of sin is to submit to Christ's authority over us. To deny His lordship is to seek justification with an impenitent faith, which is no faith.
Though our good works do not merit salvation, they are the basis upon which God promises to distribute rewards in heaven. Our entrance into the kingdom of God is by faith alone. Our reward in the kingdom will be according to our good works, which is, as Augustine noted, a case of God's gracious crowning of His own gifts.