Why is faith in Christ's sacrifice essential for salvation?

The sermon emphasizes that true faith recognizes the futility of human efforts to achieve righteousness before God. Abel exemplified this by bringing a lamb, acknowledging both God's holiness and his own sinfulness. The act of faith is portrayed as understanding that only through the blood of Christ can one approach God. This understanding is reinforced by the concept of imputed righteousness—believers are seen as righteous not based on their merits but because they are united with Christ and His perfect righteousness is credited to them.