How do we know faith without works is insufficient?

In James 2:14, the inquiry is made: 'What doth it profit, my brethren, though a man say he hath faith, and have not works? Can faith save him?' This question encourages us to realize that authentic faith is demonstrable through our actions. James continues to provide illustrations of faith being made alive by deeds, such as when Abraham's faith was validated through the action of offering his son Isaac. The essence of true saving faith is that it results in a transformation that drives the believer to act according to God’s commandments. Hence, works are not a means of earning salvation but rather a natural outflow of true faith, evidencing that one’s life has been changed by Christ.