The three "alones" of Reformation theology are: 1) Christ alone, 2) faith alone, and 3) grace alone. For Luther, these three concepts were interrelated responses to the question of how one can know God is favorable. Christ alone (as revealed in Scripture) is the source of salvation. Faith alone is the means by which one appropriates Christ's salvation. And salvation is by grace alone, not works, demonstrating God's favor is unmerited. The three alones thus form the foundation of Luther's understanding of how sinners are justified before God.