How do we know that faith alone is sufficient for salvation?

Faith alone is a fundamental tenet of Reformed theology, encapsulated in Ephesians 2:8-9, which states, 'For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast.' This underscores the truth that salvation cannot be earned or achieved through human efforts or moral measures. It highlights that God's grace is unmerited and offered freely through faith in Jesus Christ. The Reformed understanding emphasizes that true faith involves total reliance on Christ's work and not on one's merit. This doctrine fundamentally reassures the believer that their salvation rests firmly on the completed work of Christ rather than their own righteousness.